Both the spectrum and correlation characteristics are important in constructing excitation sequences to realize the multichannel ultrasonic sensors working together. For LFM excitation sequence, there should not be too many simultaneously fired ultrasonic sensors, because of the limited available frequency band of the ultrasonic ranging system. The optimized CFM excitation sequences are propose...

tio2 /fe3o4 nanocomposites with various tio2:fe3o4 ratios were synthesized by an ultrasonic-assisted deposition-precipitation method and their uv-light decolorization of congo dye and magnetic separation were investigated. the nanocomposite samples were characterized by scanning electron microscopy (sem), powder x-ray diffraction (xrd), surface area analayzer (bet) and fourier transform infrare...

Double-side replication of polymer substrates is beneficial to the design and the fabrication of 3-demensional devices. The ultrasonic embossing method is a promising, high efficiency and low cost replication method for thermoplastic substrates. It is convenient to apply silicon molds in ultrasonic embossing, because microstructures can be easily fabricated on silicon wafers with etching techni...

The measurement principle of the transit time difference method of the ultrasonic flowmeter is presented. The hardware structure and realization method are introduced. The software function and work mode are overviewed. In order to enhancing flowmeter's precision and stability a Xilinx CoolRunner CPLD and a Texas Instruments microcontroller from MSP430 family are applied in high precision timin...

continuous exposure to high-energy ultrasonic waves depolymerises macromolecules in solutions and produces a permanent reduction in viscosity. different factors affect the efficiency of this ultrasonic depolymerisation. in this work ultrasonic degradation of one commercially important hydrogel based on acrylic acid and acrylamide was carried out in aqueous solution at room temperature (25oc). a...

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transduc...

The fluids speed measurement, particularly the air speed measurement is very important for industrial and laboratory applications. The ultrasonic method is among the most common methods used for determining the air speed. The basic principle to measure a fluid speed, using an ultrasonic transducer, is based on the modification of the apparent propagation speed of an ultrasonic signal caused by ...

The process of cast explosive solidification molding has been dynamic monitored by multi-channel ultrasonic transmission method. It presents the regular pattern of ultrasonic attenuation, velocity and waveform in this process. The results show that velocity values and waveform are relative to solidification speed and physical characterization on the phase border, and ultrasonic attenuation is r...

time-of-flight diffraction method (tofd) is an amplitude-independent sizing method which is based on the measurement of time-of-flight of defect tip diffracted waves. although tofd can measure through-wall length of defect accurately, this method is not capable of measuring horizontal defect size. in this paper, a new tofd method for evaluating horizontal planar defects is presented. the finite...

PURPOSE A variety of instruments, including circular staplers, ultrasonic scalpels, lasers, and bipolar electrothermal devices, are currently used when performing a hemorrhoidectomy. This study compared outcomes between hemorrhoidectomies performed with an ultrasonic scalpel and conventional methods. METHODS The study was a randomized prospective review of data available between May 2013 and ...