Morphological evolution of tunnel tips for aluminum foils during DC etching

The morphologies of tunnel tips in different stages for aluminum foils during DC etching in 1.5 mol/L HC1 solution at 90℃ were observed by field emission scanning electron microscopy （FE-SEM）. A novel model was proposed to describe the morphological evolution of tunnel tips throughout the growth processes. In the pit nucleation stage, the pits vary from the hemispherical to half-cubic shapes due to the activation of pit tips from the center to the edge. During the tunnel growth stage, the pits dissolve toward the depth direction and develop into the tunnels, and their tips remain flat. In the tip passivation stage, as the passivation of tunnel tips speeds up from the edge to the center＇s the tunnel tips change from flat shapes to three-dimensional protrusions. The mechanism may be attributed to the order of activation or passivation on the tunnel tips changed in different stages.

Effect of tunnel structure on the specific capacitance of etched aluminum foil

The morphology of etched aluminum foil was observed using scanning electron microscopy, which led to the establishment of a cylindrical model and two merged models, considering the fixed weight loss of etching. The maximum of specific capacitance and the cor- responding optimum values for tunnel sizes at various anodization voltages were predicted. The increased size distribution and taper of tun- nels were demonstrated to decrease the specific capacitance, whereas the addition of polymeric additive into the ttmnel widening solution was demonstrated to increase the capacitance. The formation of merged tunnels on the etched aluminum surface, irrespective of the presence of row-merged tunnels or cluster-merged tunnels, resulted in a dramatic decrease in the specific capacitance. It is concluded that, enhancing the uniformity of turmel size and distribution and avoiding the formation of merged tunnels are the effective approach to achieving the higher capacitance for the tunnel etched and formed aluminum foil.

Effects of HNO_3 concentration on the pit morphologies of aluminum foil etched in HNO_3–HCl and HNO_3–H_2SO_4–HCl solutions

In this work, the effects of HNO3 concentration on the pit morphologies of high-cubic-texture aluminum foil etched in HNO3-HCl and HNO3-H2SO4-HCl solutions were investigated. When the aluminum foil was etched in HNO3-HCl solutions, the morphologies of pits transformed from irregular tunnels to typical tunnels （as inverted pyramids） and shallow cuboids as the HNO3 concentration in the etchant solution was increased. However, as the HCl concentration in the etchant solution was increased, the morphologies of pits transformed from shallow cuboids to typical tunnels （as inverted pyramids） and irregular tunnels. When the aluminum foil was etched in n N HNO3-（7.2-n） N H2SO4-0.8 N HCl solutions, the morphologies of the pits transformed from typical tunnels （i.e., the number of sub-tunnels formed on the main tunnels increased） to irregular tunnels （corrugated tnnnels and polyline tunnels） as the HNO3 concentration in the etchant solution was increased. These effects are attributed primarily to corrosion on the （100） and （010） faces of pits being accelerated and to the （001） faces be- ing prone to passivation to different degrees when various concentrations of HNO3 are added to the etchant solutions.

Prophylaxis with intraocular pressure lowering medication and glaucomatous progression in patients receiving intravitreal anti-VEGF therapy

AIM: To investigate whether pretreatment with pressurelowering medication prior to anti-vascular endothelial factor(VEGF) injections had an effect on glaucomatous progression in patients with preexisting glaucoma or ocular hypertension(OHT).METHODS: A total of 66 eyes from 54 patients with a preexisting diagnosis of glaucoma or OHT, treated with six or more anti-VEGF injections were selected for chart review. Primary outcome measures were rate of visual field loss in d B/year, rate of change in retinal nerve fiber layer(RNFL) thickness in microns/year, and need for additional glaucoma intervention.RESULTS: The number of eyes requiring additional glaucoma medication was 5 of 20(25.0%) and 14 of 46(30.4%) for the pretreated and non-pretreated groups, respectively. The number of eyes requiring glaucoma laser or surgery was 4 of 20(20.0%) and 13 of 46(28.3%) for the pretreated and non-pretreated groups, respectively. Estimated mean rate of pattern standard deviation decline was not significant in either group(P>0.073), with no difference between groups(P=0.332). Although both groups showed significant RNFL change from baseline(P<0.011), no difference was detected between groups(P=0.467).CONCLUSION: Pretreatment has no detectable effect on structural or functional glaucomatous progression. Patients receiving repeated injections may be at risk for glaucomatous complications requiring invasive intervention.