2,704 research outputs found
Thermal Conductance for Single Wall Carbon Nanotubes
We report a theoretical analysis of the phonon thermal conductance, \kappa
(T), for single wall carbon nanotubes (SWCN). In a range of low temperatues up
to 100K, \kappa (T) of perfect SWCN is found to increase with temperature,
approximately, in a parabolic fashion. This is qualitatively consistent with
recent experimental measurements where the tube-tube interactions are
negligibly weak. When the carbon-carbon bond length is slightly varied, \kappa
(T) is found to be qualitatively unaltered which implies that the anharmonic
effect does not change the qualitative behavior of \kappa (T).Comment: Revtex, 4 figure
4-Benzyl-3,5-dimethyl-1H-pyrazole
In the title molecule, C12H14N2, the dihedral angle between the pyrazole and phenyl ring mean planes is 78.65 (19)°. In the crystal, molecules are linked by N—H⋯N hydrogen bonds into chains along [010]
Phase diagram and exotic spin-spin correlations of anisotropic Ising model on the Sierpi\'nski gasket
The anisotropic antiferromagnetic Ising model on the fractal Sierpi\'{n}ski
gasket is intensively studied, and a number of exotic properties are disclosed.
The ground state phase diagram in the plane of magnetic field-interaction of
the system is obtained. The thermodynamic properties of the three plateau
phases are probed by exploring the temperature-dependence of magnetization,
specific heat, susceptibility and spin-spin correlations. No phase transitions
are observed in this model. In the absence of a magnetic field, the unusual
temperature dependence of the spin correlation length is obtained with JJ, and an interesting crossover behavior between different
phases at JJ is unveiled, whose dynamics can be described by the
JJ-dependence of the specific heat, susceptibility and spin
correlation functions. The exotic spin-spin correlation patterns that share the
same special rotational symmetry as that of the Sierpi\'{n}ski gasket are
obtained in both the plateau disordered phase and the plateau
partially ordered ferrimagnetic phase. Moreover, a quantum scheme is formulated
to study the thermodynamics of the fractal Sierpi\'{n}ski gasket with
Heisenberg interactions. We find that the unusual temperature dependence of the
correlation length remains intact in a small quantum fluctuation.Comment: 9 pages, 12 figure
N′-(2-Methoxybenzylidene)nicotinohydrazide
The title compound, C14H13N3O2, was prepared by the reaction of 2-methoxybenzyaldehyde with nicotinic acid hydrazide in methanol. The dihedral angle between the benzene and pyridine rings is 5.9 (3)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds, leading to the formation of chains along the c axis; adjacent chains are linked via C—H⋯O and C—H⋯N hydrogen bonds
Tetrakis(3,5-dimethyl-1H-pyrazole-κN 2)(nitrato-κ2 O,O′)cadmium(II) nitrate
The title compound, [Cd(NO3)(C5H8N2)4]NO3, was prepared by reaction of cadmium nitrate and 3,5-dimethylpyrazole in ethanol solution. The Cd atom adopts a distorted cis-CdO2N4 octahedral geometry involving four dimethylpyrazole molecules and one bidentate nitrate anion. The molecular structure and packing are stabilized by N—H⋯O and C—H⋯O inter- and intramolecular hydrogen-bonding interactions
N-(1H-1,2,3-Benzotriazol-1-ylmethyl)phthalimide
The title compound [systematic name: 2-(1H-1,2,3-benzotriazol-1-ylmethyl)isoindole-1,3-dione], C15H10N4O2, was prepared by the reaction of 1H-benzotriazole and 2-bromomethylisoindole-1,3-dione. The benzotriazole and isoindole units are almost planar and make a dihedral angle of 70.2 (1)° (mean planes include C and N atoms). A weak C—H⋯O intramolecular hydrogen bond involving a carbonyl O atom as acceptor stabilizes the observed molecular conformation
Resistance to Helium Bubble Formation in Amorphous SiOC/Crystalline Fe Nanocomposite
The management of radiation defects and insoluble He atoms represent key challenges for structural materials in existing fission reactors and advanced reactor systems. To examine how crystalline/amorphous interface, together with the amorphous constituents affects radiation tolerance and He management, we studied helium bubble formation in helium ion implanted amorphous silicon oxycarbide (SiOC) and crystalline Fe composites by transmission electron microscopy (TEM). The SiOC/Fe composites were grown via magnetron sputtering with controlled length scale on a surface oxidized Si (100) substrate. These composites were subjected to 50 keV He+ implantation with ion doses chosen to produce a 5 at% peak He concentration. TEM characterization shows no sign of helium bubbles in SiOC layers nor an indication of secondary phase formation after irradiation. Compared to pure Fe films, helium bubble density in Fe layers of SiOC/Fe composite is less and it decreases as the amorphous/crystalline SiOC/Fe interface density increases. Our findings suggest that the crystalline/amorphous interface can help to mitigate helium defect generated during implantation, and therefore enhance the resistance to helium bubble formation
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