Capacitive transducers are widely used in fundamental physics experiments, seismology, Earth or planetary observations, and space scientific and technical applications because of their high precision, simple structure, and compatibility with various measurements. However, in real applications, there is a trade-off between their resolution and dynamic range. Therefore, this paper is aimed at enlarging the dynamic range while ensuring high resolution. In this paper, a noise analysis of a capacitive transducer is presented, which shows that the amplitude noise of the carrier wave is the main limiting factor. Hence, a new method of generating a carrier wave with lower-amplitude noise is proposed in the paper. Based on the experimental verification, it is found that the carrier wave produced through the new method performed significantly better than the typical digital carrier wave when they were compared in the same sensing circuit. With the carrier wave produced through the new method, the dynamic range of the capacitive transducer can reach 120.7 dB, which is 18.3 dB greater than for the typical direct digital synthesis (DDS) method. In addition, the resolution of the carrier wave is mainly limited by the voltage reference components.
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http://dx.doi.org/10.3390/s20040992 | DOI Listing |
Phys Eng Sci Med
January 2025
School of Biological Science and Medical Engineering, Beihang University, 37 Xueyuan Road, Haidian District, Beijing, 100191, China.
Extracorporeal shock wave therapy (ESWT) achieves its therapeutic purpose mainly through the biological effects produced by the interaction of shock waves with tissues, and the accurate measurement and calculation of the mechanical parameters of shock waves in tissues are of great significance in formulating the therapeutic strategy and evaluating the therapeutic effect. This study utilizes the approach of implanting flexible polyvinylidene fluoride (PVDF) vibration sensors inside the tissue-mimicking phantom of various thicknesses to capture waveforms at different depths during the impact process in real time. Parameters including positive and negative pressure changes (P, P), pulse wave rise time ([Formula: see text]), and energy flux density (EFD) are calculated, and frequency spectrum analysis of the waveforms is conducted.
View Article and Find Full Text PDFInnovation (Camb)
January 2025
Center for High Pressure Science and Technology Advanced Research, Beijing 100193, China.
The steep temperature gradient near the bottom of the mantle is known to generate a negative correlation between the shear wave velocity ( ) and the depth in most regions of the D″ layer, as detected by seismological observations. However, increasing with depth is observed at the D″ layer beneath Central America, where the Farallon slab sinks, and the origin of this anomaly has not been well constrained. Here, we calculate the thermoelastic constants and obtain the elastic wave velocities of hydrous phase H with various Al contents and cation configurations, which may act as a water carrier to the D″ layer.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
Halide perovskite optoelectronic devices achieve high energy conversion efficiencies. However, their efficiency decreases significantly with an increase in temperature. This decline is likely caused by changes in nonradiative recombination and electron-phonon coupling, which remain underexplored.
View Article and Find Full Text PDFJAMA Netw Open
January 2025
Alzheimer Center Limburg, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
Importance: Baseline cerebral microbleeds (CMBs) and APOE ε4 allele copy number are important risk factors for amyloid-related imaging abnormalities in patients with Alzheimer disease (AD) receiving therapies to lower amyloid-β plaque levels.
Objective: To provide prevalence estimates of any, no more than 4, or fewer than 2 CMBs in association with amyloid status, APOE ε4 copy number, and age.
Design, Setting, And Participants: This cross-sectional study used data included in the Amyloid Biomarker Study data pooling initiative (January 1, 2012, to the present [data collection is ongoing]).
Biosens Bioelectron
January 2025
Innovation Center of Functional Genomics and Molecular Diagnostics Technology of Gansu Province, Lanzhou, China.
Improving the sensitivity of biosensor has always the major challenge to measure lower detection concentration of biological samples. In this paper, a novel optical fiber surface plasmon resonance (SPR) biosensor based on TiC MXene/GNRs synergistically highly enhanced sensitivity was proposed. The TiC MXene and GNRs were coated on the optical fiber sensing probe by the electrostatic layer-by-layer (ELBL) assembly method.
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