نتایج جستجو برای: boron nitride nanotube nuclearquadrupole resonance
تعداد نتایج: 258270 فیلتر نتایج به سال:
The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of boron nitride which functions in cosmetics as a slip modifier (ie, it has a lubricating effect). Boron nitride is an inorganic compound with a crystalline form that can be hexagonal, spherical, or cubic; the hexagonal form is presumed to be used in cosmetics. The highest reported concentration of use of boron nitride is ...
By applying the nonequilibrium Green's functions and the density-functional theory, we investigate the electronic structures and transport properties of fluorinated zigzag-edged boron nitride nanoribbons. The results show that the transition between half-metal and semiconductor in zigzag-edged boron nitride nanoribbons can be realized by fluorination at different sites or by the change of the f...
Polymer composites with high thermal conductivity have recently attracted much attention, along with the rapid development of the electronic devices toward higher speed and performance. However, a common method to enhance polymer thermal conductivity through an addition of high thermally conductive fillers usually cannot provide an expected value, especially for composites requiring electrical ...
The design of stacks of layered materials in which adjacent layers interact by van der Waals forces has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties as well as the emergence of novel physical phenomena and device functionality. Here, we report photoinduced doping in van der Waals heterostructures consisting of graphene ...
Hexagonal boron nitride sheets have been noted especially for their enhanced properties as substrates for sp(2) carbon-based nanodevices. To evaluate whether such enhanced properties would be retained under various realistic conditions, we investigate the structural and electronic properties of semiconducting carbon nanotubes on perfect and defective hexagonal boron nitride sheets under an exte...
The geometric and electronic structure of a buried monolayer of boron nitride ~BN! has been probed using resonant soft x-ray fluorescence ~SXF!. By using the strong p* resonance feature in the resonant fluorescence spectrum near the B (1s) threshold, we were able to detect the BN thin film and examine changes in its electronic structure when the monolayer is placed between different materials. ...
Single-wall boron nitride nanotubes samples synthesized by laser vaporization of a hexagonal BN target under a nitrogen atmosphere are studied by UV and visible Raman spectroscopy. We show that resonant conditions are necessary for investigating phonon modes of BNNTs. Raman excitation in the UV (229 nm) provides preresonant conditions, allowing the identification of the A1 tangential mode at 13...
density functional theory ,(dft) calculations have been performed to investigate the properties ofcarbon decorated (c-decorated) models of boron nitride (bn) nanocones. to this aim, the apex andtip of nanocone have been substituted by the carbon atoms to represent the c-decorated models. theresults indicated that dipole moments and energy gaps could reveal the effects of c-decorations onthe pro...
Past molecular dynamics (MD) studies of boron nitride nanotubes (BNNTs) have used van der Waals parameters from generic force fields, combined with various values for the partial charges on the boron and nitrogen atoms. This study explores the validity of these parameters by first using quantum chemical packages Car-Parrinello molecular dynamics (CPMD) and Gaussian to compute partial charges fo...
We report the application of our dc SQUID (superconducting quantum interference device) spectrometer [C. Connor, J. Chang, and A. Pines, Rev. Sci. Instrum. 61, 1059( 1990)] to nuclear quadrupole resonance (NQR) studies of aluminum-27, and boron-II in crystalline and glassy solids. Our results give eqQ /h = 2.38 MHz and 1] = 0.0 for a-A120 3 at 4.2 K. For the natural mineral petalite (LiAISi4 01...
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