نتایج جستجو برای: ultrasonic effect
تعداد نتایج: 1666322 فیلتر نتایج به سال:
This work compares efficiencies of pneumatic and ultrasonic nebulizers and discusses drawbacks observed in trace element analyses of environmental matrices using ICP-AES with ultrasonic nebulization. The interference observed is mainly due to variable calcium content in samples; in most cases the excessive plasma loading by Ca is responsible for signal suppression of analyte elements. Such matr...
In the present work, decomposition of o-chlorophenol (2-cp) was carried out using an ultrasonic process. The extent of 2-cp decomposition depends on several parameters such as ultrasound wave energy (ultrasonic amplitude), addition of hydrogen peroxide (H2O2), pH value (H+ concentration), ionic strength, and initial concentration of 2-cp. The experimental results showed that the decomposition o...
An electric field built inside a crystal was proposed to enhance photoinduced carrier separation for improving photocatalytic property of semiconductor photocatalysts. However, a static built-in electric field can easily be saturated by the free carriers due to electrostatic screening, and the enhancement of photocatalysis, thus, is halted. To overcome this problem, here, we propose sonophotoca...
Impregnating wood, assisted with ultrasound technology, could improve the impregnation efficiency by improving the permeability of wood, thus affecting the subsequent drying process. Poplar lumber and phenolic resin were applied to investigate the influence of ultrasound-assisted impregnation on the wood drying process. The ultrasonic frequency and processing time were analyzed and correlated. ...
Wear behavior is influential to improve friction drive and wear lifespan of actuators or motors, which work at an elliptical locus vibration. Sliding wear tests of metallic friction pairs are conducted by a laboratory rig of ultrasonic vibration. Surfaces of the different metallic sliders are characterized using surface roughness, Abbott curves and fractal dimension. Results show that surface r...
BACKGROUND Phytosterols have important physiological and officinal function. METHODS An efficient ultrasonic assisted extraction, purification and crystallization procedure of phytosterols was established from corn silk for the first time. RESULTS The orthogonal test was applied to optimize the process parameters and a maximum phytosterols recovery as high as 10.5886 mg/g was achieved by ul...
Noninvasive focused ultrasound stimulation (FUS) can be used to modulate neural activity with high spatial resolution. Phase-amplitude coupling (PAC) between neuronal oscillations is tightly associated with cognitive processes, including learning, attention, and memory. In this study, we investigated the effect of FUS on PAC between neuronal oscillations and established the relationship between...
This paper presents a spikes removing methodology for ultrasonic rangefinders with an application to a quadrotor unmanned aerial vehicle. Ultrasonic sensors suffer from spikes in distance measurements due to specular reflectance and acoustic noise. Removing these spikes is necessary for improving the hovering performance of the quadrotor. The spikes removing algorithm is based on the discrete w...
The excess ultrasonic attenuation caused by adding glycogen and inorganic phosphate to liver homogenates has been studied to determine the underlying differences between attenuation coefficients of normal and diffusely diseased livers. Results show that glycogen has a higher than average specific absorption coefficient compared to other large molecular weight biomolecules. Since the glycogen co...
This clinical investigation examined the effect of chlorhexidine, sanguinarine and saline as coolants during ultrasonic scaling on gingivitis in orthodontic patients. Eighteen females with gingivitis participated in this study. Plaque Index (PI), Gingival Index (Gl), Interdental Bleeding Index (Bl) and Probing Depth (PD) were recorded for the following teeth 16, 21, 25, 36, 41 and 45 at baselin...
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