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Two distinct configurations of the monovacancy in graphene have been observed using aberration-corrected transmission electron microscopy (AC-TEM) at 80 kV. The predicted lower energy asymmetric monovacancy (MV), exhibiting a Jahn-Teller reconstruction (r-MV), has been observed, but in addition, we have imaged instances of a symmetric monovacancy (s-MV). We(More)
Defects in graphene alter its electrical, chemical, magnetic and mechanical properties. The intentional creation of defects in graphene offers a means for engineering its properties. Techniques such as ion irradiation intentionally induce atomic defects in graphene, for example, divacancies, but these defects are randomly scattered over large distances.(More)
A simple method is presented for synthesizing large single crystal graphene domains on melted copper using atmospheric pressure chemical vapor deposition (CVD). This is achieved by performing the reaction above the melting point of copper (1090 °C) and using a molybdenum or tungsten support to prevent balling of the copper from dewetting. By controlling the(More)
Focused electron beam irradiation has been used to create mono and divacancies in graphene within a defined area, which then act as trap sites for mobile Fe atoms initially resident on the graphene surface. Aberration-corrected transmission electron microscopy at 80 kV has been used to study the real time dynamics of Fe atoms filling the vacancy sites in(More)
Recent studies have revealed that several Gram-negative species utilize variations of the well-known chemotaxis signaling cascade to switch lifestyles in order to survive environmental stress. The two survival strategies covered in this review are the development of dormant cyst cells and biofilm formation. Each of these structures involves(More)
We show that controlling the introduction time and the amount of sulphur (S) vapour relative to the WO3 precursor during the chemical vapour deposition (CVD) growth of WS2 is critical to achieving large crystal domains on the surface of silicon wafers with a 300 nm oxide layer. We use a two furnace system that enables the S precursor to be separately heated(More)
Genomic and genetic analyses have demonstrated that many species contain multiple chemotaxis-like signal transduction cascades that likely control processes other than chemotaxis. The Che₃ signal transduction cascade from Rhodospirillum centenum is one such example that regulates development of dormant cysts. This Che-like cascade contains two hybrid(More)
The relative prevalence of various configurations of the tetravacancy defect in monolayer graphene has been examined using aberration corrected transmission electron microscopy (TEM). It was found that the two most common structures are extended linear defect structures, with the 3-fold symmetric Y-tetravacancy seldom imaged, in spite of this being a low(More)
Ripples in graphene are an out-of-plane distortion that help stabilize suspended monolayer graphene. The introduction of disclinations and dislocations into the lattice of graphene is predicted to extensively ripple graphene to form "hillocks" to accommodate the strain in the system. Here, we confirm this theoretical prediction by intentionally introducing(More)