Inkjet printing of a liquid suspension prepared by dispersing silver powders of size around 4 nm in deionized (DI) water at 30 wt% was investigated in this study. By comparing with the results of pure DI water, the effects of nanoparticles on droplet formation between the nozzle and the substrate were also studied. A bipolar pulse waveform was employed in driving the piezoelectric printhead with pulse voltage set as the primary variable of this study. Observations showed that a higher driving pulse voltage was required for the silver suspension to form droplets than DI water. The liquid column broke up at the nozzle orifice for DI water while the silver suspension broke up further away below the nozzle office. It was also observed that the droplet size of the silver suspension was smaller than that of DI water. For the silver suspension the liquid column formed was thinner and longer and the pinch-off time of the liquid column to form droplets was also longer. However, the characteristic adjustment time for droplet recombination was shorter for the silver suspension than for DI water.

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A 14-year old girl with lupus erythematosus (LE) who initially showed as discoid lupus and followed with nephrotic syndrome one year later. Concomitant piroxicam and indomethacin were prescribed for her arthritis, which preceded two months before the onset of nephrotic syndrome. Histology from renal biopsy showed minimal-change nephrotic syndrome (MCNS). After continuous treatment for six months, nephrotic syndrome resolved completely and no signs of relapse were noted over 14 years of follow-up. For the children, it is rare to have both LE and MCNS simultaneously; sequela of nonsteroidal anti-inflammatory drugs also seldom results in nephrotic syndrome. Though their relationship is still not defined, the possibility of LE combined with MCNS must be differentiated in patients with lupus and severe proteinuria.

An experimental investigation on the droplet formation of molten Sn3.0 wt%Ag0.5 wt%Cu alloy by an inkjet printing process was conducted. The printing process used a piezoelectric print head with a nozzle orifice diameter of 50 μm. Micro-droplets of a molten lead-free solder were ejected at 230 • C. The print head was driven by a bipolar pulse 40 V in amplitude. The major variables for this study were two pulse times; t rise /t finalrise and t fall , as well as N 2 back-pressure in the molten solder reservoir. Under various printing conditions, extrusion of the liquid column, contraction of liquid thread and pinch-off of liquid thread at nozzle exit were observed by monitoring the dynamics of the molten solder droplet ejection process. The droplet formation was found to be insensitive to t rise and t finalrise in the range of 250-1000 μs. The behavior of droplet formation was, however, significantly affected by the transfer rate, t fall , in the range of 30-60 μs and t fall of 50 μs yielded the most desirable condition of single droplet formation. The N 2 back-pressure was also found to be critical, where a back pressure between 10 and 21 kPa could give the desirable single-droplet formation condition.

Aqueous silver nitrate inks of 1, 5, and 10 mol/liter (M) were employed in a piezoelectric inkjet printing apparatus to construct microstructural patterns. On the basis of droplet observation, single droplets of silver nitrate inks were ejected at a suitable pulse amplitude of waveform. The characteristics of drying processes for silver nitrate solutions were investigated after measuring the contact angle on the prepared glass substrates. Because of the crystallization of silver nitrate, the decrease of local surface tension was induced with decreasing solute concentration. In addition, local surface tension was possibly reduced by exothermal reaction during the formation of crystal solid. The actual printing qualities of array and line patterns were then analyzed by variation of dot interval and substrate temperature. The pure silver patterns were reduced by ethylene glycol vapor at 250 °C for 10 min. Unsteady spreading features of printed array and line patterns on hydrophilic glass are found to be due to silver nitrate crystal during droplet drying, which is dominated by solute concentration and substrate temperature. Optimal printing quality with a continuous morphology of fine lines was generated successfully with a dot interval of 40 μm and an average line width of 90 μm at substrate temperature of 90 °C.