نتایج جستجو برای: boron carbide synthesis
تعداد نتایج: 434147 فیلتر نتایج به سال:
The effects of stoichiometry on the atomic structure and the related mechanical properties of boron carbide (B(4)C) have been studied using density functional theory and quantum molecular dynamics simulations. Computational cells of boron carbide containing up to 960 atoms and spanning compositions ranging from 6.7% to 26.7% carbon were used to determine the effects of stoichiometry on the ato...
Boron carbide (B4C) added manganese dioxide (MnO2) used as a cathode material for a Zn–MnO2 battery using aqueous lithium hydroxide (LiOH) as the electrolyte is known to have higher discharge capacity but with a lower average discharge voltage than pure MnO2 (additive free). The performance is reversed when using potassium hydroxide (KOH) as the electrolyte. Herein, the MnO2 was mixed with 0, 5...
Boron carbide nanoparticles were made via a reaction of boron, obtained from thermal decomposition of magnesium diboride, with multiwall carbon nanotubes at 1150 ◦C for 3 h in vacuum. The size of the nanoparticles is smaller than 100 nm. The bamboo structure of the multiwall carbon nanotubes is the key to the successful synthesis of such nanoparticles. Good crystallinity was demonstrated by sca...
This thesis is a theoretical study of configurational disorder in icosahedral boronrich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of eff...
We contrast the interaction of mercury with adsorbed orthocarborane films and semiconducting (dehydrogenated) boron carbide. Photoemission spectra reveal small shifts in orthocarborane (C2B10H12) molecular orbital binding energies as well as the shift in mercury 5d5/2 shallow core level binding energies, suggesting only small interaction between mercury and the molecular film. Mercury does, how...
Commercial EUV lithographic systems require multilayers with higher reflectance and better stability then that published to date. Interface-engineered MoISi multilayers with 70% reflectance at 13.5 nm wavelength (peak width of 0.545 nm) and 71% at 12.7 nm wavelength (peak width of 0.49 nm) were developed. These results were achieved with 50 bilayers. These new multilayers consist of Mo and Si l...
Catalyst-free growth of boron carbide nanowires is achieved by pyrolysis of diborane and methane at 650–750 -C and around 500 mTorr in a quartz tube furnace. Electron-diffraction analysis using a novel diffraction-scanning transmission electron microscopy (D-STEM) technique indicates that the crystalline nanowires are single-crystal orthorhombic boron carbide. TEM images show that the nanowires...
In this study, TiB2 particles were synthesized by sol-gel method in nanometer size. First, the sol was prepared in a four-component system of alkoxide -boron carbide -water-alcohol based on the sol-gel chemical process under acidic conditions at pH = 5. Titanium tetra-isopropoxide and boron carbide were used as raw materials. After hydrolysis and gel formation followed by heat treatment, TiB2 n...
Abstract Spectroscopic investigations are made on expanding plasma plumes created by a 20 ns, 3 J laser pulse impinging perpendicularly onto targets of boron, boron carbide and boron nitride. The characterization of the plasma plumes is carried out spectroscopically in the wavelength range from 30 to 330 Å, and by taking pinhole pictures at shorter wavelengths. The experimental results are comp...
The structural and electronic properties of nickeland phosphorus-doped boron–carbon (B5C) alloy thin films grown by plasma-enhanced chemical vapor deposition have been examined. The Ni-doped boron–carbon alloys were grown using closo-1,2-dicarbadodecaborane (C2B10H12) as the boron–carbon source compound and nickelocene (Ni(C5H5)2) as the nickel source. The phosphorus-doped alloys were grown usi...
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