Reactions of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz) with solvated first-row transition metals M(II) (M(II) = Ni, Zn, Mn, Fe, Cu) have been explored with emphasis on the factors that influence the identity of the resulting cyclic products for Ni(II) and Zn(II). The relatively small anions, namely [ClO4]- and [BF4]-, lead to the formation of molecular squares [{M4(bptz)4(CH3CN)8} subsetX][X]...

Forming a regular pentagon, decagon and pentagram using origami technique is based on the construction of approximately 36 angle by dint of A4 paper of format. The implemented method is “fold and cut”. We endeavored to obtain the polygons with the most accurate sides, i.e. with the minimal aberration of the interior angle. There is also considered an ideal paper format, which would provide the ...

Defects are common but important in graphene, which could significantly tailor the electronic structures and physical and chemical properties. In this study, the density functional theory (DFT) method was applied to study the electronic structure and catalytic properties of graphene clusters containing various point and line defects. The electron transfer processes in oxygen reduction reaction ...

Fullerene-Like (FL) sulpho-carbide (CSx) compounds have been addressed by first principles calculations. Geometry optimization and cohesive energy results are presented for the relative stability of precursor species such as C2S, CS2, and C2S2 in isolated form. The energy cost for structural defects, arising from the substitution of C by S is also reported. Similar to previously synthesized FL-...

The optical excitations in C70 and higher fullerenes, including isomers of C76, C78, and C84, are theoretically investigated. We use a tight binding model with long-range Coulomb interactions, treated by the Hartree-Fock and configuration-interaction methods. We find that the optical excitations in the energy region smaller than about 4 eV have most of their amplitudes at the pentagons. The osc...

The rise in defense spending since 1998, which this year may surpass 100% in real terms, is unprecedented over a 48-year period. In real percentage term, it is nearly as large as the Kennedy-Johnson and Reagan surges combined. Whether one looks at the entire DoD budget or just that part not related to the wars, current spending is above the peak years of the Vietnam era and the Reagan years. Lo...

In this paper we consider the achievable rate region of the Gaussian Multiple Access Channel (MAC) when suboptimal transmission schemes are employed. Focusing on the two-user MAC and assuming uncoded Pulse Amplitude Modulation (PAM), we derive a rate region that is a pentagon, and propose a strategy with which it can be achieved. We also compare the region with outer bounds and with orthogonal ...

We show that every pair of hexagons in a fullerene graph satisfying the isolated pentagon rule (IPR) forms a resonant pattern. This solves a problem raised by Ye et al. [SIAM J. Discrete Math. 23(2):2009, p. 1023–1044].