- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Micro‐CT study on the removal of accumulated hard‐tissue debris from the root canal system of mandibular molars when using a novel laser‐activated irrigation approach
摘要： Aim To compare the efficacy of ultrasonically activated irrigation (UAI), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photoacoustic streaming (SWEEPS) activation for the removal of accumulated hard-tissue debris (AHTD) from the root canal system of mandibular molars when assessed using microcomputed tomography (micro-CT). Methodology A total of 30 mandibular first and second molars with joining mesial root canals containing an isthmus and a single distal canal were subjected to three micro-CT scans (before and after canal instrumentation and after final irrigation) at a resolution of 15 μm. Mesial canals were prepared up to Protaper F3 rotary file, and distal canals were prepared up to Protaper F4 rotary file. Teeth were randomly assigned to 3 groups according to the irrigant activation method (n = 10): the UAI group, the PIPS group, and the SWEEPS group. The final irrigation procedures were performed using a total of 15.5 mL of 1% NaOCl for each tooth with an activation time of 3 × 30 s. After three-dimensional model reconstruction and volumetric measurement of root canals, the percentage reduction (%Rd) of AHTD was calculated. The %Rd of AHTD was analyzed statistically using one-way analysis of variance and nonparametric tests at a significance level of 5%. Results There were no significant differences between the three groups in terms of canal volume before or after instrumentation, or the volume of debris after canal preparation (P > 0.05). In the mesial canals, irrigation with SWEEPS reduced the overall debris by 84.31%, which was significantly more than the reduction associated with PIPS and UAI (58.79% and 50.27%, respectively). In the distal canals, the %Rd of AHTD was significantly different between PIPS and SWEEPS and between UAI and SWEEPS (P < 0.05), but was not significantly different between PIPS and UAI groups (P > 0.05). The SWEEPS had higher %Rd of AHTD than the PIPS and UAI groups. Conclusions SWEEPS was associated with significantly less debris compared than PIPS and UAI, especially in isthmus-containing mesial roots. None of the activation techniques completely removed debris from root canal systems.
关键词： ultrasonic,photoacoustic streaming,irrigation,hard-tissue debris
更新于2025-09-12 10:27:22
-
Ultrasonic and microwave assisted extraction as rapid and efficient techniques for plant mediated synthesis of quantum dots: green synthesis, characterization of zinc telluride and comparison study of some biological activities
摘要： In this study, a simple, rapid, and efficient plant-mediated green approach was presented for the synthesis of stable and ultra-small zinc telluride quantum dots (ZnTe QDs) using the aqueous extract of the Ficus johannis plant. Two modern techniques, namely ultrasonic and microwave techniques, were applied to prepare the plant extracts, which were then used as stabilizing precursors in the synthesis of ZnTe QDs. The synthesized samples were characterized via different techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption, photoluminescence and Fourier transform infrared spectroscopy. The TEM images confirmed the formation of ultra-small nanoparticles with an average size of 8 nm. According to the optical characterization, a wide absorption band around 390 nm and an intense emission peak at 463 nm clarified the successful synthesis of ZnTe QDs. After synthesis and characterization, the antioxidant, antimicrobial, and antifungal potentials of the as-prepared QDs as well as the plant extracts were examined by different tests, comparatively. In addition, the determination of the total phenolic and flavonoid contents of the as-prepared samples was carried out. Moreover, the toxicity of the samples was investigated by Artemia uramiana from their brine shrimp lethality potentials. In the cytotoxicity tests, the inhibition of root growth was considered as an indicator to evaluate the cytotoxicities of the samples.
关键词： Ultrasonic,quantum dots,microwave,biological activities,extraction,green synthesis,zinc telluride
更新于2025-09-11 14:15:04
-
Broadband Laser Ultrasonic Excitation and Multi-band Sensing for Hierarchical Automatic Damage Visualization
摘要： It is well known that the selection of a frequency for signal generation and data acquisition signi?cantly affects the quality of ultrasonic or laser ultrasonic nondestructive testing (NDT) results, and the analog ?lter is essential to prevent the aliasing effect. This paper presents a systematic approach using a hierarchical inspection scheme for automatic inspection processes. A frequency band divider (FBD) with a single-input–multiple-output (SIMO) system was newly created to examine quickly various frequency ranges at single scanning using laser-based broadband excitation. The FBD was implemented into a pulse-echo ultrasonic propagation imaging (PE UPI) system capable of fully noncontact laser ultrasonic inspection. Only two scans are required to determine the optimal frequency range for unknown specimens. This tremendously reduces the number of scanning trials for the investigation of complete frequency ranges.
关键词： Nondestructive testing,Programmable band-pass ?lter,Pulse-echo ultrasonic propagation imager,Hierarchical approach
更新于2025-09-11 14:15:04
-
Effective Defect Features Extraction for Laser Ultrasonic Signal Processing by Using Time–Frequency Analysis
摘要： The time-frequency analysis (TFA) by wavelet transform is adopted for the laser ultrasonic signal processing, and the effective features extraction of the material defect is obtained. The TFA is adopted here to analyze the laser-generated surface acoustic wave (SAW) signal which contains the defect features, the echo wave features are extracted signi?cantly, especially under the condition of low signal-to-noise rate (SNR). The simulation model by using ?nite element method (FEM) is set up in an aluminum plate with different surface defect depths in detail, and the defect depths prediction with TFA is also considered. It shows that, without extra denoising process, the echo SAW is extracted signi?cantly in case of defect depths ranging from 0.1mm to 0.9mm at SNR of ?3dB by TFA. The TFA for processing the laser ultrasonic signal provides a promising way to get the defect information, with the accuracy increased by 7.9dB in this work, which is extremely meaningful for the ultrasonic signal processing and material evaluation.
关键词： Time-frequency analysis,feature extraction,wavelet transform,signal-to-noise rate,laser ultrasonic signal
更新于2025-09-11 14:15:04
-
Effect of the Substrate Temperature on the Properties of SnO<sub>2</sub> Thin Films Prepared by Ultrasonic Spray for Solar Cells Applications
摘要： Structural, optical properties of SnO2 thin films deposited by spray ultrasonic technique were investigated by varying substrate temperature. The structural characterization of the films was analyzed via X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). These studies indicated that the layers were polycrystalline. Films surface morphologies were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optical absorption spectrum was recorded using the UV-VIS-NIR spectroscopy and the films were found to be transparent. The optical transmittance varied with substrate temperature from 60–80% over a wide range of wavelength. Optical measurements showed that the layers had a relatively high absorption coefficient of 105 cm?1. A shift in the absorption edge was observed and the films exhibited direct transitions with band gap energies ranging from 3.85 to 3.94 eV.
关键词： transparent and conductive tin dioxide,SnO2 thin films,spray ultrasonic technique,substrate temperature
更新于2025-09-11 14:15:04
-
Spatial distribution of the phononic crystal modes excited by a moving laser source
摘要： In this paper, we have presented the dispersion curve of Lamb waves in an aluminum plate with a periodic rectangular corrugation experimentally. A mode selection method was applied to generate Lamb waves in the region of the corrugated periodic structure using a moving continuous wave laser, and the signal can be detected at any point in the excitation region. The relationship between the phase velocity and the frequency is observed. It is found that the intensity distribution of the dispersion curves in the experimental results is related to the slope of the dispersion curves as well as the selection of the detection point. Vibrations at a series of locations were detected, re?ecting the change in energy that Lamb waves undergo in the process of propagation through the periodic structure, which is different from the existing method of single-point excitation and detection. The spatial distribution of the mode amplitude at the resonances points, in particular induced by the Bragg re?ection, has been studied.
关键词： dispersion curve,phononic crystal,Bragg reflection,laser ultrasonic method,Lamb waves
更新于2025-09-11 14:15:04
-
Young’s double-slit interference enabled by surface plasmon polaritons: a review
摘要： Red yeast rice has been utilized for colouring food, brewing wine and preserving meat, which is also used as a folk medicine for centuries. In this study, a water-soluble non-starch polysaccharide from red yeast rice (RYRP) was extracted by using ultrasonic-assisted extraction method. By using Box–Behnken design (BBD) to optimize the parameters for extracting the RYRP, the maximum extraction yield (3.37%±0.78%) was obtained under the optimal extraction conditions as follows: ratio of water to raw material (40 mL/g), extraction temperature (62 °C), extraction time (75 min) and ultrasonic power (200 W). Moreover, monosaccharide composition analysis showed that RYRP was consisted of mannose, glucosamine, glucose and galactose with a molar ratio of 0.152:0.015:1:0.149. The molecular weight distribution analysis showed that the average molecular weight of the RYRP fraction was about 3.49 × 103 Da. Furthermore, RYRP exhibited significant antioxidant activities in vitro and the gastrointestinal-protective effect in vivo using gastrointestinal disorders (GD) model mice. RYRP could be explored as a potential source in the pharmaceutical and functional food industries.
关键词： Polysaccharide,Ultrasonic-assisted extraction,Red yeast rice,Antioxidant activities,Structural characterization,Gastrointestinal-protective effect
更新于2025-09-11 14:15:04
-
Noncontact photoacoustic angiography with an air-coupled ultrasonic transducer for evaluation of burn injury
摘要： In vivo identi?cation of viable and thermally coagulated blood in a burn wound can be used to pro?le the type, extent, and site of the burn, thus assisting the removal of necrotic tissue in preparation for skin grafts. Recently, intensive research on photoacoustic imaging (PAI) has been conducted to evaluate burn injury. However, most PAI systems usually take the approach of direct physical contact of an acoustic detector or an impedance matching medium with the vulnerable burned skin, which exposes signi?cant limitations on the diagnosis of burn injuries. Here, we present a noncontact PAI system, based on a custom designed air-coupled ultrasonic transducer, enabling in vivo noncontact vasculature to be imaged without contrast agents. Using the natural difference in light absorption between coagulated and non-coagulated blood at the wavelength of 532 nm, this PAI system possesses an immanent advantage to discriminate viable and thermally coagulated blood in burned tissues. Phantom experiments and burned rabbit’s skin imaging have been implemented to demonstrate that the noncontact PAI technique could be valuable in the adjuvant diagnosis and observation of burns.
关键词： air-coupled ultrasonic transducer,noncontact,photoacoustic imaging,burn injury,vasculature
更新于2025-09-11 14:15:04
-
[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Cathodoluminescence Characterization of Semiconductor Doping at the Nanoscale
摘要： PVDF pyroelectric sensor was widely used in many fields. At present, the PVDF pyroelectric sensor has been applied for acoustic measurement. However, the effect of backing on the sensitivity of sensor was not particularly studied until now. In this paper, a Physical model was established in the finite element software. According to this model, the waveform of pyroelectric signal was predicted. By changing the parameters of the backing material, the influence of the backing on the sensitivity of the sensor was analyzed. It is confirmed that the Physical model is effective and the constant pressure heat capacity, attenuation coefficient and acoustic impedance of backing material directly affect the sensitivity of the sensor.
关键词： PVDF pyroelectric sensor,backing material,ultrasonic power,sensitivity
更新于2025-09-11 14:15:04
-
High-throughput screening of laser additive manufactured metallic glass via ultrasonic wave
摘要： Laser additive manufacturing (LAM) technology provides an opportunity to fabricate bulk metallic glasses (BMGs) without any dimensional constraint and achieve the large-scale applications of BMGs. However, flaws, such as cracks, gas porosity, and crystalline phases, are always formed accompanied by the process of LAM, which seriously worsens the mechanical and physical properties of the resulting BMGs. Here, we present a novel method that involves ultrasonic wave technique to high-throughput screen the optimum process parameters for the LAM of BMG. A parameter library, constituted by a series of rectangular BMG samples, is rapidly fabricated by the LAM method under continuously changed combinations of laser power and travel speed. the ultrasonic attenuation factor, which is sensitive to the flaws, is used as the monitor to screen the parameters of the BMGs fabricated by the LAM. Using this approach, the laser power of 1300 W and travel speed of 600 mm/min are estimated as the optimum parameter combination for the LAM of a Zr51ti5ni10cu25Al9 (Zr51) BMG with the slightest flaws. The amorphous-phase dominated microstructure and the sufficiently high tensile strength of the subsequent fabricated large-sized Zr51 BMG sample verify this optimum parameter combination.
关键词： High-throughput screening,Bulk metallic glasses,Ultrasonic wave testing,Optimum process parameters,Laser additive manufacturing
更新于2025-09-11 14:15:04