Numerical model of shear module of alginate micro-beads under ultrasonic thermal effect / 军事医学

Objective To establish a numerical model of the shear module of alginate beads stimulated by ultrasonic sound.Methods The compression ratio and force of alginate beads were recorded with the compression test .The shear module of beads was measured with a Hertz model .When to alginate beads were stimulated ultrasonically for different durations , the ultrasonic stimulation power , ultrasonic pulse ratio , and changes in the shear module and solution temperature were measured.Results Temperatures in the solution and shear module of alginate beads increased under different ultrasonic stimulation conditions .Modeling analysis revealed the relationship between the shear module of alginate beads and the corresponding temperature .The shear module of beads was in a quadratic equation with temperature (20℃

A bipolar optocoupler isolation amplifier with high precision and wide bandwidth / 生物医学工程学杂志

To fit the technological requirements in electrical impedance tomography system, an improved bipolar optocoupler isolation amplifier based on single analog optocoupler was realized. The experimental results illustrates that the full power -3dB bandwidth of this circuit is greater than 800 KHz, the equivalent output noise is lower than 50 uV(RMS), and the linearity at +/- 4 V inputs is lower than 0.01%. In addition to these features, the circuit also have the advantages of simple structure and no distortion caused by mismatch between analog optocouplers.

Frequency characteristic of diseased breast tissues detected by electrical impedance scanning / 生物医学工程学杂志

The rules of conductance parameters on diseased breast tissue, which change with the driven frequency, are studied by use of electrical impedance scanning. This work is intended to provide a basis for further examination of breast. We have obtained conductance parameters' frequency characteristic of three kinds of breast diseases, i.e. invasive ductal carcinoma, neoplastic hyperplasia, and mastopathia. And by comparison, we find that the frequency characteristic of the diseased breast tissues is different from that of the peripheral normal tissues, and the frequency characteristic shows differences among the three kinds of diseased breast tissues. So, we are able to identify the kind of breast disease by its frequency characteristic.