A wet etch process that produces smooth sidewalls aligned with the m-plane ({1!100}) crystal facets of Ga-polar GaN grown on sapphire is demonstrated by combining photo-electrochemical (PEC) treatment with a postprocessing wet etch step. This novel process results in faceted and extremely smooth vertical etched sidewalls. This two-step process consists of a PEC treatment to define the geometry ...

The kinetics of photoelectrochemical (PEC) oxidation of methanol, as a model organic substrate, on α-Fe2O3 photoanodes are studied using photoinduced absorption spectroscopy and transient photocurrent measurements. Methanol is oxidized on α-Fe2O3 to formaldehyde with near unity Faradaic efficiency. A rate law analysis under quasi-steady-state conditions of PEC methanol oxidation indicates that ...

Pulsed eddy current (PEC) non-destructive testing and evaluation (NDT&E) has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the literature covering ...

To investigate the influence of the Morin transition on the photoelectrochemical (PEC) activity of hematite, electronic properties in different magnetic phases were studied on the basis of the first-principles calculations within the GGA+U approximation. The results show that the effective electron mass in the (0001) plane changes remarkably due to the spin−flop transition, while the effective ...

We have engineered the electronic structure at the interface between Cu2O and ZnO nanorods (NRs) array, through adjusting the carrier concentration of Cu2O. The electrodeposition of Cu2O at pH 11 acquired the highest carrier concentration, resulting in the largest interfacial electric field between Cu2O and ZnO, which finally led to the highest separation efficiency of photogenerated charge car...

oil and gas transmission pipelines are critical items of infrastructure in providing energy sources to regions and countries. steel pipes are commonly used which can be subject to both internal and external corrosion. this paper presents an advanced nondestructive inspection technique for detection of oil-gas pipeline corrosion defect. the pulsed eddy current (pec) method has been successfully ...

Percutaneous endoscopic colostomy (PEC) was first described in 1986, by Jeffrey Ponski [1], who had invented percutaneous endoscopic gastrostomy a few years before that [2]. Performed by 2 operators, PEC consists of placing a tube in the colon during colonoscopy in order to provide antegrade colonic enemas (ACE) in severe constipation or fecal incontinence [3,4]. The PEC tube can also be used a...

Prediction error curves are increasingly used to assess and compare predictions in survival analysis. This article surveys the R package pec which provides a set of functions for efficient computation of prediction error curves. The software implements inverse probability of censoring weights to deal with right censored data and several variants of cross-validation to deal with the apparent err...