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Integrated effects of fractional laser microablation and sonophoresis on skin immersion optical clearing in vivo
摘要： This study is aimed to find an approach for effective skin optical clearing in vivo using polyethylene glycol 300 (PEG-300) as an optical clearing agent in combination with physical enhancers: fractional laser microablation (FLMA), and/or low-frequency sonophoresis. In this study albino outbred rats were used. Light attenuation coefficient and optical clearing potential of these approaches were evaluated in upper (from ~70 to ~200 μm) and middle (from ~200 to ~400 μm) dermis separately using optical coherence tomography (OCT). In 30 min, optical clearing potential of sonophoresis in combination with FLMA and PEG-300 in the upper dermis was the maximal (2.3±0.4) in comparison with other treatments in this time point. The most effective approach for optical clearing of middle dermis was PEG-300 and sonophoresis; but the maximal value of optical clearing potential (1.6±0.1) was achieved only in 90 min.
关键词： Optical Coherence Tomography,Laser Tissue Ablation,Immersion,Ultrasonic Therapy,Skin
更新于2025-09-23 15:21:01
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CaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> -based lead-free sol–gel composites for high-temperature application
摘要： CaBi4Ti4O15 (CBiT)-based lead-free sol–gel composites were developed for high-temperature ultrasonic transducer application. In this study, two types of lead-free sol–gel solution, Ba0.7Sr0.3TiO3 (BST) and Bi4Ti3O12 (BiT), were used for consistency to fabricate >50-μm-thick CBiT/BST and CBiT/BiT ?lms on 3-mm-thick titanium substrates by a sol–gel spray technique. BST and BiT were chosen because of their high dielectric constant and high Curie temperature, respectively, in addition to their being lead-free materials. A thermal cycle test was carried out between RT and 600 °C, and clear multiple echoes were con?rmed during three thermal cycles for both materials. In addition, the sensitivity of CBiT/BiT was higher than that of CBiT/BST although a higher poling temperature is required for CBiT/BiT. Therefore, an ultrasonic transducer potential for high-temperature application was successfully demonstrated. ? 2018 The Japan Society of Applied Physics
关键词： ultrasonic transducer,high-temperature,sol–gel composites,lead-free,CaBi4Ti4O15
更新于2025-09-23 15:21:01
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Study of Laser-Generated Longitudinal Waves Interacting with an Internal Spherical Cavity by Use of a Transmission Time Delay Method
摘要： In order to improve the detection sensitivity and stability of scanning laser ultrasound techniques, we propose a transmission time delay method, based on the time delay of transmitted longitudinal waves, for the evaluation of the size and position of an internal cavity. By studying the interacting process between the longitudinal wave and the internal cavity through theory and finite element method, the relationships among the time delay, cavity radius, and the detection distance were determined. The monotonicity of the relationship indicates that the time delay can be used to inverse the radius and the depth position of the internal cavity. The laser ultrasound experiments were performed on three aluminum samples with different internal cavities through the concentric transmission method. The C-scan results show that compared with using amplitude attenuation to detect the cavity, the time delay of transmitted waves can detect the internal cavities more stably and accurately. The experimental data are close to the theoretical and simulation results, and the inversion of cavity depth was achieved based on the measured parameters (the time delay, cavity radius, frequency, velocity). The results demonstrate that the transmission time delay method has a great application potential in the localization and quantification of the internal defects.
关键词： Laser ultrasonic,Time delay,Longitudinal wave,Internal cavity,Creeping wave
更新于2025-09-23 15:21:01
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Smart choice of carbon dots as a dual-mode onsite nanoplatform for the trace level detection of Cr2O72-
摘要： Efficient ways for the trace level monitoring of Cr2O7 2? have generated considerable attention in the fields of medical diagnosis and environmental protection. In current research, the water-soluble carbon dots (CDs) have been developed via the precursors of 1,3-phenylenediamine and citric acid. The quantum dots with particle size of 3–4 nm have been prepared based on a simple one-pot ultrasonic irradiation method and demonstrate bright blue emission at 440 nm. Its excitation-dependent feature has been explored and the achieved emission evolves from blue (440 nm) to green luminescence (528 nm). Photophysical studies support that CDs can be remarkably quenched by the presence of chromate due to inner filter effect. In addition, the absorption curves demonstrate that carbon dots possess highly selective and sensitive responses to Cr2O7 2? through color changes. The dual sensing modes (fluorescence and colorimetric detection) can be well-established for the recognition of chromate and the detection limits are calculated to be as low as 140 nM and 410 nM respectively. To further evaluate the analytical potentials of such nano-platform, the concentration of Cr2O7 2? have been determined in real water and river samples.
关键词： Ultrasonic,Luminescence,Carbon dots,Sensor
更新于2025-09-23 15:21:01
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A Novel Topology for Process Variation-Tolerant Piezoelectric Micromachined Ultrasonic Transducers
摘要： This paper presents a novel architecture for piezoelectric micromachined ultrasonic transducers (PMUT) allowing for a drastic reduction in the impact of process variations on the accuracy of the resonant frequency. At the core of this new topology is a toroidal anchoring technique. Measurement results show that inter- and intra-die resonant frequency standard variations can be reduced from 101 kHz to 23 kHz and from 20 kHz to 5.9 kHz, respectively, by using the method proposed in this paper, showcasing devices fabricated using the PiezoMUMPs commercial fabrication technology. From the 16 chips that have been fabricated, each holding 12 PMUT devices of two different topologies, resonant frequency results are presented and analyzed to assess the effectiveness of the proposed approach. In addition, as a proof of concept, the fabricated PMUT are demonstrated to perform distance ranging measurements.
关键词： frequency,ranging measurements,variability,process variation,MEMS,PMUT,Piezoelectric ultrasonic transducers,microfabrication
更新于2025-09-23 15:21:01
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Synthesis of BiOCl Nanosheets by a Simple Ultrasonic Route
摘要： Ternary bismuth oxyhalide (BiOX, X = F, Cl, Br, I) with layered structure have emerged as promising photocatalysts for water splitting and environmental remediation. Ultrathin BiOCl nanosheets were achieved by a simple ultrasound way. The product was characterized by XRD, SEM and TEM.
关键词： Ultrathin,Nanosheets,BiOX,Ultrasonic
更新于2025-09-23 15:21:01
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Efficacy of photodynamic therapy vs ultrasonic scaler for preventing gingival inflammation and white spot lesions during orthodontic treatment
摘要： The effectiveness of Photodynamic therapy (PDT) was compared vs ultrasonic scaler (US) as prophylactic methods for oral decontamination during the orthodontic treatment. There were no statistically significant differences in FMPS, FMBS, PD, ICDAS scores and counts of P. gingivalis, P.intermedia and mutans streptococci at T1, T2 and T3 follow-ups. Based in the protocol designed, PDT and US allowed in a similar way to control the extent of the enamel demineralization until 6 months post-treatment and the progression of the gingival inflammation until 9 months post-treatment.
关键词： gingival inflammation,ultrasonic scaler,orthodontics,Photodynamic therapy,white spots
更新于2025-09-23 15:21:01
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Orientation factor and piezoelectric property in textured (K,Na)NbO <sub/>3</sub> system ceramics with minimal templates
摘要： To lower the sintering temperature and decrease the weight ratio of templates required for fabricating textured (K,Na)NbO3 (KNN) system ceramics, the method of preparing platelike NaNbO3 (NN) single-crystal particles for the templates was improved. The NN crystal particles synthesized by the single-step molten salt method using a mixed salt were treated by ultrasonic vibration and subsequently screened. Using these improved templates, we developed the fabrication method for the textured KNN system ceramics by which the weight ratio of the templates required for the orientation control can be reduced to 1/10 of the conventional weight ratio. The effects of decreasing the weight ratio of templates on sintering temperature, orientation factor, and piezoelectric properties were investigated. In addition, the effects of adding Bi2O3 to KNN calcined powder were also studied to suppress abnormal grain growth, which appears in the textured samples fabricated using smaller amounts of the templates.
关键词： reactive template grain growth,molten salt synthesis,Bi2O3 addition,lead-free piezoelectric materials,ultrasonic treatment,textured ceramics
更新于2025-09-23 15:21:01
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Measurement of shallow defects using noncontact broadband leaky Lamb wave produced by pulsed laser with ultrasound microphone
摘要： In this study, we propose a convenient noncontact laser ultrasonic system to detect small cracks and estimate the wall-thinning defects of thin plates. The system uses an ultrasound microphone to detect the energy leaked from the broadband Lamb-wave propagation. The broadband characteristics of this wave, produced by a pulsed laser, are used to measure the wavenumber. The cumulative standing-wave energy (CSWE) method that uses a traveling wave is implemented to verify the feasibility of the ultrasound microphone. The excitation energy of the pulsed laser was insufficient compared with that of the continuous-wave contact actuator. Therefore, a modified local wavenumber estimation (LWE) method is proposed, which reconstructs several LWE images at various frequencies. These images are averaged to calculate thicknesses of the plate and defects, by using the wavenumber–thickness relationship. The method has an error of 2.84% and 7.7% for the thickness of the plate and defect area, respectively.
关键词： cumulative standing-wave energy (CSWE),ultrasound microphone,local wavenumber estimation (LWE),wall-thinning defects,noncontact laser ultrasonic system,broadband Lamb-wave propagation,small cracks
更新于2025-09-23 15:19:57
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Highly efficient flexible perovskite solar cells made via ultrasonic vibration assisted room temperature cold sintering
摘要： With emerging flexible substrates, perovskite solar cells have entered into a new stage of development toward flexibility, portability and miniaturization. However, this promising landscape is hindered by the necessity the high-temperature processes. In this study, a highly efficient, stable and flexible planar perovskite solar cell is fabricated using an all-room temperature pathway. First, a nanocrystalline SnO2 layer is deposited on polyethylene terephthalate/indium tin oxide via room-temperature sol-gel strategy. Then (FAPbI3)0.85(MAPbBr3)0.15 is coated thereon, by annealing-free solution deposition. In both steps films are subjected to ultrasonic vibration, right after deposition, while they are still wet. By virtue of the ultrasonic energy, surface evaporation of liquid molecules is accelerated, impurities are removed from deposited wet film, and as a result shrinkage and sintering occur at room temperature. The cell is completed by a classical method, showing a champion power conversion efficiency of 17.38%, based on 0.16 cm2 active area. After 480 h aging in 50% relative humidity, this cell retains 80% of its initial performance. This research promises efficient, inexpensive and sustainable systems for harvesting solar energy by wearable modules.
关键词： SnO2,Cold sintering,Ultrasonic vibration,Perovskite solar cells,Flexible
更新于2025-09-23 15:19:57