A rapid and non-invasive method for measuring the peak positive pressure of HIFU fields by a laser beam

Based on the acousto-optic interaction, we propose a laser deflection method for rapidly, non-invasively and quantitatively measuring the peak positive pressure of HIFU fields. In the characterization of HIFU fields, the effect of nonlinear propagation is considered. The relation between the laser deflection length and the peak positive pressure is derived. Then the laser deflection method is assessed by comparing it with the hydrophone method. The experimental results show that the peak positive pressure measured by laser deflection method is little higher than that obtained by the hydrophone, confirming that they are in reasonable agreement. Considering that the peak pressure measured by hydrophones is always underestimated, the laser deflection method is assumed to be more accurate than the hydrophone method due to the absence of the errors in hydrophone spatial-averaging measurement and the influence of waveform distortion on hydrophone corrections. Moreover, noting that the Lorentz formula still remains applicable to high-pressure environments, the laser deflection method exhibits a great potential for measuring HIFU field under high-pressure amplitude. Additionally, the laser deflection method provides a rapid way for measuring the peak positive pressure, without the scan time, which is required by the hydrophones

The selective synthesis of single-crystalline CdS nanobelts and nanowires by thermal evaporation at lower temperature

CdS nanobelts and nanowires were successfully synthesized by simple thermal evaporation of CdS powder at a temperature as low as 650 degrees C, using pure H-2 as a carrier gas. The morphology of the products could be conveniently controlled by adjusting the deposition parameters. Electron microscopy studies of the materials showed that the single-crystalline CdS nanowires have a diameter of 200 nm and a length of tens of micrometres, and the nanobelts are 100 - 200 nm in width, 30 nm in thickness and tens of micrometres in length. High-resolution transmission electron microscopy demonstrated that the nanobelts, which are different from the nanowires growing along the [0001] direction, have three types of growth direction: [2 (1) over bar(1) over bar0], [01 (1) over bar0] and [0001]. It is demonstrated that a reductive carrier gas, such as hydrogen, plays an important role in the whole growth process of CdS nanowires and nanobelts

Myrica rubra Extracts Protect the Liver from CCl4-Induced Damage

The relationship between the expression of mitochondrial voltage-dependent anion channels (VDACs) and the protective effects of Myrica rubra Sieb. Et Zucc fruit extract (MCE) against carbon tetrachloride (CCl4)-induced liver damage was investigated. Pretreatment with 50 mg kg−1, 150 mg kg−1 or 450 mg kg−1 MCE significantly blocked the CCl4-induced increase in both serum aspartate aminotransferase (sAST) and serum alanine aminotransferase (sALT) levels in mice (P < .05 or .01 versus CCl4 group). Ultrastructural observations of decreased nuclear condensation, ameliorated mitochondrial fragmentation of the cristae and less lipid deposition by an electron microscope confirmed the hepatoprotection. The mitochondrial membrane potential dropped from −191.94 ± 8.84 mV to −132.06 ± 12.26 mV (P < .01) after the mice had been treated with CCl4. MCE attenuated CCl4-induced mitochondrial membrane potential dissipation in a dose-dependent manner. At a dose of 150 or 450 mg kg−1 of MCE, the mitochondrial membrane potentials were restored (P < .05). Pretreatment with MCE also prevented the elevation of intra-mitochondrial free calcium as observed in the liver of the CCl4-insulted mice (P < .01 versus CCl4 group). In addition, MCE treatment (50–450 mg kg−1) significantly increased both transcription and translation of VDAC inhibited by CCl4. The above data suggest that MCE mitigates the damage to liver mitochondria induced by CCl4, possibly through the regulation of mitochondrial VDAC, one of the most important proteins in the mitochondrial outer membrane

Connected Vibrating Piezoelectric Bimorph Beams as a Wide-band Piezoelectric Power Harvester

We analyze coupled flexural vibration of two elastically and electrically connected piezoelectric beams near resonance for converting mechanical vibration energy to electrical energy. Each beam is a so-called piezoelectric bimorph with two layers of piezoelectrics. The 1D equations for bending of piezoelectric beams are used for a theoretical analysis. An exact analytical solution to the beam equations is obtained. Numerical results based on the solution show that the two resonances of individual beams can be tuned as close as desired by design when they are connected to yield a wide-band electrical output. Therefore, the structure can be used as a wide-band piezoelectric power harvester

A rapid and non-invasive method for measuring the peak positive pressure of HIFU fields by a laser beam

Based on the acousto-optic interaction, we propose a laser deflection method for rapidly, non-invasively and quantitatively measuring the peak positive pressure of HIFU fields. In the characterization of HIFU fields, the effect of nonlinear propagation is considered. The relation between the laser deflection length and the peak positive pressure is derived. Then the laser deflection method is assessed by comparing it with the hydrophone method. The experimental results show that the peak positive pressure measured by laser deflection method is little higher than that obtained by the hydrophone, confirming that they are in reasonable agreement. Considering that the peak pressure measured by hydrophones is always underestimated, the laser deflection method is assumed to be more accurate than the hydrophone method due to the absence of the errors in hydrophone spatial-averaging measurement and the influence of waveform distortion on hydrophone corrections. Moreover, noting that the Lorentz formula still remains applicable to high-pressure environments, the laser deflection method exhibits a great potential for measuring HIFU field under high-pressure amplitude. Additionally, the laser deflection method provides a rapid way for measuring the peak positive pressure, without the scan time, which is required by the hydrophones

Transient non-Fourier thermal interactions of two parallel cracks in porous metal foam

Experimental evidence shows heat conduction in the porous media would be non-Fourier under specific circumstances. The novelty of this research lies in considerations of the non-Fourier effect and the interactions of two parallel thermally insulated cracks in the porous metal foam. The transient propagation characteristics are examined by utilizing the Dual-phase-lag model, which incorporates the certain time required to establish local thermal equilibrium between the solid framework and surrounding pores. Fourier transform and Laplace transform are employed to solve the mathematical model simulating a porous strip subjected to abrupt thermal shock. After reducing the problem to two groups of singular integral equations, the transient temperature distributions and heat flux intensity factors are determined with the help of numerical Laplace inversion. Numerical calculations are carried out to evaluate the impacts of crack positions, the relative density, phase lags, and two crack lengths on the thermal characteristics, which would contribute to a thorough understanding of the ultrafast process of porous materials operating in extreme conditions

The catalyst-assisted synthesis of high quality CdS single-crystal nanowires through an epitaxy mechanism

High-quality wurtzite CdS nanowires have been synthesized by thermal evaporation of CdS powder onto Si substrate in the presence of Au catalyst at 650 degrees C by using pure H-2 as a carrier gas. The nanowires were 10 nrn in diameter and a few tens of micrometers in length. XRD patterns demonstrated that as prepared CdS is a pure crystalline material. High-resolution transmission electron microscopy of the materials showed that all CdS nanowires grew along 0001). According to analysis of selective area electron diffraction patterns taken from the interface, we proposed that there is a kind of epitaxy relationship in the interface region between Au catalyst and CdS grown, i.e., (0001)(CdS) parallel to (111)Au, and [1210](CdS) parallel to [011](Au)

Quantum Computing Enhanced Distance-Minimizing Data-Driven Computational Mechanics

The distance-minimizing data-driven computational mechanics has great potential in engineering applications by eliminating material modeling error and uncertainty. In this computational framework, the solution-seeking procedure relies on minimizing the distance between the constitutive database and the conservation law. However, the distance calculation is time-consuming and often takes up most of the computational time in the case of a huge database. In this paper, we show how to use quantum computing to enhance data-driven computational mechanics by exponentially reducing the computational complexity of distance calculation. The proposed method is not only validated on the quantum computer simulator Qiskit, but also on the real quantum computer from OriginQ. We believe that this work represents a promising step towards integrating quantum computing into data-driven computational mechanics.Comment: 22 pages, 14 figure