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Herein we report a one‐step, low cost, photocatalytic method for the synthesis of graphene oxide (GO) from commercial graphite using grey TiO2 as a photocatalyst. GO formation is achieved by UV‐illumination of a slurry of well‐dispersed grey TiO2 and commercial graphite. Light‐induced valence‐band holes from grey TiO2 then lead to an oxidation and exfoliation of graphite, resulting in the formation of visible‐light‐active GO. An optimal level of graphite oxidation can be established by controlling the UV illumination time. Moreover, the resulting GO‐decorated TiO2 is directly active as a visible‐light‐active photocatalyst that can, for example, be used for pollution degradation. [ABSTRACT FROM AUTHOR]

We studied the effects of photomask design, illumination time, and UV intensity on the formation of polymer walls, and speculated the related mechanism. According to the optimized condition, we make a flexible LCD cell with colorless polyimide substrate. [ABSTRACT FROM AUTHOR]

The effect of gate shape and its necessary fabrication process on the reliability of AlGaN/GaN high electron mobility transistors (HEMT) was studied on devices fabricated on the same wafer, using DC and pulsed HEMT analysis. Simulations were used to determine the difference in electric field on the surface and in the barrier for the three gate shapes studied, I-shaped, slanted, and recessed slanted. Prior to each electrical characterization during stress, devices were exposed to ultraviolet illumination to probe only newly generated traps rather than the filling of pre-existing electronic traps. Degradation was seen to increase with electric field strength; in each device type traps were generated by device stress at the location of the peak electric field. It was found that HEMTs with I-shaped gates showed larger degradation under the same stress conditions than devices with slanted gates. This was due to a higher electric field at the interface between the SiN x passivation and the AlGaN barrier layer resulting in higher surface trap generation. HEMTs with slanted recessed gates showed indications of barrier trapping while surface trapping effects played a smaller role. [ABSTRACT FROM AUTHOR]

Recent findings showed that transiently accessing structurally native-like yet energetically higher conformational states is sufficient to trigger the formation of protein fibrils. Typically, these conformational states are made available through changing solvent conditions or introducing mutations. Here we show a novel way to initialize fibril formation for Chicken egg white lysozyme (CEWL) under native conditions via controlled UV illumination. Through a cassette of tryptophan-based photochemistry, the two terminal disulfide bonds in CEWL can be selectively reduced. The reduced CEWL is then converted to conformational states with the C-terminal fragment floppy upon thermal fluctuation. These states serve as precursors for the fibrillar aggregation. Intriguingly, the CEWL fibrils are stabilized by intermolecular disulfide bonds instead of noncovalent β-sheet structures, distinct from the amyloid-like lysozyme fibrils reported before. Based on the experimental evidences and all-atom molecular dynamics simulation, we proposed a 'runaway domain-swapping' model for the structure of the CEWL fibrils, in which each CEWL molecule swaps the C-terminal fragment into the complementary position of the adjacent molecule along the fibrils. We anticipate that this fibrillation mechanism can be extended to many other disulfide-containing proteins. Our study stands for the first example of formation of protein fibrils under native conditions upon UV illumination and poses the potential danger of low UV dose to organisms at the protein level. Proteins 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]