13C NMR Spectroscopy of Amorphous Hydrogenated Carbon and Amorphous Hydrogenated Boron Carbide

1998 ◽  
Vol 555 ◽  
Author(s):  
Janet Braddock-Wilking ◽  
Shiu-Han Lin ◽  
Bernard J. Feldman
Keyword(s):  
Boron Carbide ◽  
Theoretical Calculations ◽  
Nanocrystalline Structure ◽  
13C Nmr Spectroscopy ◽  
Aromatic Rings ◽  
Carbide Matrix ◽  
High Boron ◽  
Amorphous Hydrogenated Boron Carbide ◽  
Amorphous Hydrogenated Carbon ◽  
Carbon Peak

AbstractWe report the 13C NMR spectra of amorphous hydrogenated carbon and boron carbide. The amorphous hydrogenated carbon spectra consist primarily of a sp2 carbon peak at 40 ppm and a sp3 carbon peak at 140 ppm and are in reasonable agreement with recent theoretical calculations of Mauri, Pfrommer, and Louie, but there are some noteable discrepancies. The amorphous hydrogenated boron carbide spectra are very different from that of amorphous hydrogenated carbon, showing two sharp lines at 135 and 170 ppm at low boron concentrations and an intense, broader line at 15 ppm at high boron concentrations. We suggest the two sharp lines at 135 and 170 ppm could be due to carbon atoms in boron-containing aromatic rings, and the broader line at 15 ppm as due to carbon atoms in boron carbide icosahedra. These lines provide evidence of nanocrystalline structure imbedded in an amorphous hydrogenated boron carbide matrix.

13CNMR spectroscopy of amorphous hydrogenated carbon and amorphous hydrogenated boron carbide

1999 ◽  
Vol 59 (15) ◽  
pp. 9745-9747 ◽  
Author(s):  
Janet Braddock-Wilking ◽  
Shu-Han Lin ◽  
Bernard J. Feldman
Keyword(s):  
Boron Carbide ◽  
Amorphous Hydrogenated Boron Carbide ◽  
Amorphous Hydrogenated Carbon

scholarly journals Nanoscale Structure-Property Relationship in Amorphous Hydrogenated Boron Carbide for Low-k Dielectric Applications

2017 ◽  
Vol 23 (S1) ◽  
pp. 1486-1487
Author(s):  
Soohyun Im ◽  
Michelle M. Paquette ◽  
Mohammed Belhadj-Larbi ◽  
Paul Rulis ◽  
Ridwan Sakidja ◽  
...  
Keyword(s):  
Boron Carbide ◽  
Structure Property ◽  
Property Relationship ◽  
Structure Property Relationship ◽  
Nanoscale Structure ◽  
Amorphous Hydrogenated Boron Carbide ◽  
Low K

scholarly journals Carbon-Enriched Amorphous Hydrogenated Boron Carbide Films for Very-Low-k Interlayer Dielectrics

2017 ◽  
Vol 3 (12) ◽  
pp. 1700116 ◽  
Author(s):  
Bradley J. Nordell ◽  
Thuong D. Nguyen ◽  
Anthony N. Caruso ◽  
Sudhaunshu S. Purohit ◽  
Nathan A. Oyler ◽  
...  
Keyword(s):  
Boron Carbide ◽  
Interlayer Dielectrics ◽  
Amorphous Hydrogenated Boron Carbide ◽  
Low K

scholarly journals Model creation and electronic structure calculation of amorphous hydrogenated boron carbide: a classical/ab initio hybrid approach

RSC Advances ◽  
2017 ◽  
Vol 7 (74) ◽  
pp. 46788-46795 ◽  
Author(s):  
Mohammed Belhadj-Larbi ◽  
Rachel Cramm Horn ◽  
Paul Rulis
Keyword(s):  
Electronic Structure ◽  
Boron Carbide ◽  
Ab Initio ◽  
Hybrid Approach ◽  
Structure Calculation ◽  
Electronic Structure Calculation ◽  
Periodic Model ◽  
Amorphous Hydrogenated Boron Carbide

Periodic model of amorphous hydrogenated boron carbide.

scholarly journals Polar Alkoxy Group and Pyridyl Effects on the Mesomorphic Behavior of New Non-Symmetrical Schiff Base Liquid Crystals

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1832
Author(s):  
Sayed Z. Mohammady ◽  
Daifallah M. Aldhayan ◽  
Mohammed A. Alshammri ◽  
Ayoub K. Alshammari ◽  
Mohammed Alazmi ◽  
...  
Keyword(s):  
Schiff Base ◽  
Liquid Crystals ◽  
Chain Length ◽  
Density Functional ◽  
Theoretical Calculations ◽  
13C Nmr Spectroscopy ◽  
Alkoxy Group ◽  
Thermal Stabilities ◽  
New Compounds ◽  
Base Liquid

A series of non-symmetrical Schiff base liquid crystals were prepared and investigated. Schiff bases of p-alkyloxy aniline derivatives and 4-phenyl pyridine-4′-carbaldehyde were synthesized. The terminal alkoxy groups substituting aniline are of varied chain length, namely C6, C8, and C16. The structures of the compounds were confirmed via 1H NMR and 13C NMR spectroscopy. Different mesophases of the samples were thermally and optically characterized by differential thermal analysis (DSC) and polarized optical microscopy (POM). All samples revealed enantiotropic smectic B (SmB) and smectic A (SmA) mesophases. The results obtained were further correlated with the density functional theory (DFT) theoretical calculations. The results are compared to a series of compounds bearing biphenyl moiety in their mesogens. The thermal stabilities of the different mesophase reduced upon the increment of the alkoxy chain length. The temperature ranges of both the smectic mesophases of new compounds bearing the 4-phenyl pyridine moiety are generally expanded higher than the other series. In addition, the total mesophase range is greater in the new compounds when compared to their biphenyl analogues. The DFT results were investigated in terms of the molecular geometries and the frontier molecular orbitals as well as the charge distribution mapping to show and illustrate the difference in the mesomorphic properties.

scholarly journals Reactive sintering of B4c-TiB2 composites from B4 and TiO2 precursors

2020 ◽  
Vol 14 (4) ◽  
pp. 329-335
Author(s):  
Pavol Svec ◽  
Zuzana Gábrisová ◽  
Alena Brusilová
Keyword(s):  
Fracture Toughness ◽  
Boron Carbide ◽  
Titanium Diboride ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Reactive Sintering ◽  
Different Temperatures ◽  
Carbide Matrix

The effect of sintering temperature in the interval from 1775 to 1850?C on the density, microstructure, hardness and fracture toughness of ceramic composites consisting of a boron carbide matrix and titanium diboride secondary phase was studied. The composites were hot pressed using in situ reaction between boron carbide and 40 wt.% of titanium dioxide additive. The samples were hot pressed at different temperatures but for the constant time of 60min, under the pressure of 35MPa in vacuum of 10 Pa. Both Vickers hardness and fracture toughness of the composites increased with the sintering temperature.Maximal hardness of 29.8GPa and fracture toughness of 6.9MPa?m1/2 were achieved for the composite with 29.6 vol.% of titanium diboride secondary phase sintered at the highest sintering temperature of 1850?C.

scholarly journals Synthesis of Dinaphtho[2,3-d:2’,3’-d’]anthra[1,2-b:5,6-b’]dithiophene (DNADT) Derivatives: Effect of Alkyl Chains on Transistor Properties

2020 ◽  
Vol 21 (7) ◽  
pp. 2447
Author(s):  
Takumi Ishida ◽  
Yuta Sawanaka ◽  
Ryota Toyama ◽  
Zhenfei Ji ◽  
Hiroki Mori ◽  
...  
Keyword(s):  
Field Effect ◽  
Theoretical Calculations ◽  
Grazing Incidence ◽  
Aromatic Rings ◽  
Force Microscopy ◽  
Alkyl Chains ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Type Molecule ◽  
Effect Transistor

To investigate organic field-effect transistor (OFET) properties, a new thienoacene-type molecule, 4,14-dihexyldinaphtho[2,3-d:2’,3’-d’]anthra[1,2-b:5,6-b’]dithiophene (C6-DNADT), consisting of π-conjugated nine aromatic rings and two hexyl chains along the longitudinal molecular axis has been successfully synthesized by sequential reactions, including Negishi coupling, epoxidation, and cycloaromatization. The fabricated OFET using thin films of C6-DNADT exhibited p-channel FET properties with field-effect mobilities (µ) of up to 2.6 × 10−2 cm2 V−1 s−1, which is ca. three times lower than that of the parent DNADT molecule (8.5 × 10−2 cm2 V−1 s−1). Although this result implies that the installation of relatively short alkyl chains into the DNADT core is not suitable for transistor application, the origins for the FET performance obtained in this work is fully discussed, based on theoretical calculations and solid-state structure of C6-DNADT by grazing incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) analyses. The results obtained in this study disclose the effect of alkyl chains introduced onto the molecule on transistor characteristics.

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