Optical investigation of fast pulsed discharge on surface of ceramics for environmental applications
Pulsed surface discharge on the surface of ceramics was investigated experimentally. Photon counting method was applied to clarify preceding phase of the discharges. The results indicated the effect of charge injection from electrodes. Pulsed surface discharge reactor for decomposition of nitrogen oxides utilizing honeycomb ceramics was proposed. Framing and streak observation was carried out with image converter cameras. Emission spectra from the discharge were investigated with spectrometer. Uniform surface discharges on honeycomb ceramics were successfully obtained utilizing pulsed power generator with a SI-thyristor.
Evaluation of 5500 V-class SI-thyristor as pulsed power switching device utilizing a low inductance testing circuit
Characterization of 5500 V-class reverse conducting SI-thyristors as a pulsed power switching device was examined utilizing a low inductance testing circuit. The testing circuit consisted of nineteen doorknob type ceramic capacitors with the total capacitance of 38 nF, and had a residual inductance of less than 13 nH. The SI-thyristor, tested in this report, was specially designed for pulsed power applications. When the anode voltage of 5 kV was applied, a discharge current rose up to 4.2 kA with dl/dt of 6.8/spl times/10/sup 10/ A/s, and the anode voltage fall time reached 62 ns. The comparison with conventionally designed SI-thyristors indicated the effectiveness of the new design.
Engineering bio-inks for 3D bioprinting cell mechanical microenvironment
Three-dimensional (3D) bioprinting has become a promising approach to construct­ing functional biomimetic tissues for tissue engineering and regenerative medicine. In 3D bioprinting, bio-inks are essential for the construction of cell microenviron­ment, thus affecting the biomimetic design and regenerative efficiency. Mechanical properties are one of the essential aspects of microenvironment, which can be char­acterized by matrix stiffness, viscoelasticity, topography, and dynamic mechanical stimulation. With the recent advances in functional biomaterials, various engineered bio-inks have realized the possibility of engineering cell mechanical microenviron­ment in vivo. In this review, we summarize the critical mechanical cues of cell micro­environments, review the engineered bio-inks while focusing on the selection princi­ples for constructing cell mechanical microenvironments, and discuss the challenges facing this field and the possible solutions for them.