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Failure behaviour of graphite is non-linear with global failure occurring when local micro-failures, initiated at stress-raising pores, coalesce into a critically sized crack. This behaviour can be reproduced by discrete lattices that simulate larger scale constitutive responses, derived from knowledge of microstructure features and failure mechanisms. A multi-scale modelling methodology is presented...
Highly compressible three-dimensional graphene aerogels with anisotropic porous structure are fabricated by directional freezing of graphene hydrogel using anisotropically grown ice crystals as templates followed by freeze–drying. The directional freezing approach endows the graphene aerogel with a high compressive strength in the axial direction and good compressibility in both axial and radial directions...
We investigate the nitrogen doping of mono- and bi-layer graphene on 6H–SiC(0001) using two plasma-based methods: a lab-scale microwave plasma gun and an industrial-scale plasma-based implanter. As revealed by X-ray photoemission spectroscopy, the thickness of the pristine graphene significantly influences the bonding configuration of the incorporated nitrogen atoms. Using the plasma gun, a high concentration...
A three-layer molecular model containing Fe atoms as the top and bottom layers and polymer and carbon nanotube matrix as the core is developed and investigated to provide understandings of the improved tribology properties of the polymer composites by incorporation of carbon nanotubes as reinforcements. The investigation is conducted using molecular dynamics simulations to particularly examine the...
Ultrathin carbon foams with the thickness about 24 μm were fabricated by the pyrolysis of polyimide/graphene composite foams. The addition of graphene was verified to stabilize the porous structure of the foams and accelerate their graphitization process simultaneously. Consequently, the well-defined carbon foams exhibited much higher electromagnetic interference (EMI) shielding effectiveness (SE)...
Since controlled delivery of drug molecules to targeted sites are essential criteria for effective drug delivery, herein a porous nanocarrier chemically functionalized with the drug molecules is developed to accomplish this goal. ∼150 nm diameter porous carbon nanospheres were produced on a large scale from abundant lemon grass (Cymbopogon flexuosus) via silica etching and ball milling followed by...
A novel graphene oxide (GO)-immobilized heteroleptic iridium complex was synthesized and demonstrated as a first heterogenized homogeneous catalyst for the production of dimethylformamide (DMF) from carbon dioxide, hydrogen, and dimethylamine. The synthesized hybrid catalyst showed comparable activity as homogeneous heteroleptic iridium complex with additional benefits such as facile recovery and...
Tantalizing information about a possible existence of diamond stars has recently refocused attention of the scientific community on the basic properties of carbon-rich planets and stars. Since the carbon-rich star types are known for a usual presence of oxygen, it is not clear how carbon and oxygen can co-exist under extreme PT-conditions at a C/O < 1 atomic ratio. Therefore, the significance of...
A theoretical study of pentagon/hexagon-bearing isomers of the C32 and C86 fullerenes suggests that the diversity in electronic structure and vibrational properties is determined by the surface curvature of the fullerene cage rather than by the global bond network topology. The latter plays a greater role in small, highly constrained fullerene cages, while it can be safely ignored in the case of larger...
Simultaneous reduction and doping of the graphene oxide (GO) is an important issue for low temperature processed flexible electronic devices. A low temperature method for reduction and ambipolar doping has been developed which yield the doped reduced GO with wide range of work function with a mass production using tetra-methyl ammonium hydroxide (TMAH). The doping type of obtained reduced GO is tuned...
Graphene oxide in hard carbon/graphene composite is reduced by thermal treatment in inert atmosphere at a temperature in the range of 800–1100 °C. In this way, hard carbon/graphene composites with different effect of reduction on graphene oxide are obtained. Increasing heat treat temperature improves the reduction of graphene oxide (C/O atomic ratio in the range of 44–104) and diminishes the specific...
In this study, we present an approach to manufacture individual and array-type carbon nanotubes in a transmission electron microscope. Semiconductor nanowires are used as templates to form a core–shell structure by depositing uniform amorphous carbon layers around the nanowires using electron-beam induced deposition. Joule heating produced by an applied external voltage melts the nanowires and crystallizes...
The focus of this study is the preparation of carbon-based materials that satisfy the requirements of developing quasi-optic controllable absorbers for terahertz technology. These materials have been obtained from a commercially available organic polymer, Kapton® HN polyimide, through a pyrolysis process conducted in an inert atmosphere at different temperatures. The pyrolysis of Kapton film up to...
Novel composites made of two dimensional (2D) MoS2 nanosheets and graphene (G) have been fabricated by a combined approach of chemical vapor deposition and hydrothermal technique. The G film helps to mediate the growth and dispersion of MoS2 nanosheets, of which the unique role of G in the MoS2 growth is revealed by density functional theory study. The results show that the hexagonal lattice carbon...
The esterification of lignin with butyric anhydride decreases both the viscosity of lignin/PAN blend spinning solutions and their glass-transition temperature compared to unmodified lignin/PAN blends. The effect of blending PAN with lignin before or after butyration on the electrospinnability, miscibility and thermal stability of precursor blend fibers was investigated by morphological, rheological,...
A miniature carbon nanotube (CNT) paste emitter dot with a diameter of ∼50 μm was fabricated onto the cross-sectional surface of Kovar (nickel-cobalt ferrous alloy) rod without using a sophisticated photolithography. A highly adhesive CNT paste was prepared with silicon carbide and nickel nanoparticles, and then the small CNT emitter was fabricated by a novel and facile technique, called point contact...
A facile method for the direct synthesis of interconnected microporous carbon via carbonization of potassium acid phthalate in inert atmosphere is reported. The as-obtained microporous carbon exhibited a high specific surface area (1118 m2 g−1) and 67% of the pore volume was attributed to microporosity, which are ideal for electrodes of supercapacitors. LiNO3 electrolytes of different concentrations...
Graphene has attracted interest for a number of applications ranging from electronics, optoelectronics to membrane-based technologies. The thermal reduction of chemically exfoliated graphene oxide (GO) sheets represents an important step for large-scale, solution-based graphene synthesis. Therefore, understanding the reduction process and being able to provide new handles to control the resulting...
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