We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs). We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW) interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or as...

Fluorinated anti-fluorenacenedione 6 was newly synthesized by oxidation of a dehydro[12]annulene fused with tetrafluorobenzene 4. X-Ray crystallography of 6 demonstrated a totally planar structure and shorter intramolecular distances for F ... I, F ... O, and I ... O than the corresponding sums of van der Waals (vdW) radii. In the packing structure, molecules are arranged in a pi-stacked motif,...

Daar is vier biljoen mense in die wêreld. Veertig miljoen van hulle is blind. As die verhouding tussen bevolkingsaanwas en blindheid nie verm inder nie, sal die syfer teen die einde van die eeu verdubbel wees. Ten minste 80% van die wêreld se blindheid kom voor in die ontwikkelende lande van A sië, Afrika en Latyns-Am erika. Die Internasionale Agentskap vir die Voorkom ing van Blindheid (I .A ....

BACKGROUND Food access interventions are promising strategies for improving dietary intake, which is associated with better health. However, studies examining the relationship between food access and intake are limited to observational designs, indicating a need for more rigorous approaches. The Veggie Van (VV) program was a cluster-randomized intervention designed to address the gap between fo...

We consider a large, convenient enough class of pencils on singular complex spaces. By introducing variation maps in homotopy, we prove in a synthetic manner a general Zariski-van Kampen type result for higher homotopy groups, which in homology is known as the “second Lefschetz theorem”.

Contemporary Dutch dialects are compared using the Levenshtein distance, a measure of pronunciation difference. The material consists of data from the most recent Dutch dialect source available: the Goeman-Taeldeman-Van Reenen-Project (GTRP). This data consists of transcriptions of 1876 items for 613 localities in the Netherlands and Belgium gathered during the period 1980 – 1995. In addition t...

We investigate the van der Waals interactions in solid molecular hydrogen structures. We calculate enthalpy and the Gibbs free energy to obtain zero and finite temperature phase diagrams, respectively. We employ density functional theory (DFT) to calculate the electronic structure and density functional perturbation theory (DFPT) with van der Waals (vdW) functionals to obtain phonon spectra. We...

Structural and electronic properties of two-dimensional stanene and graphene heterostructure (Sn/G) are studied by using first-principles calculations. Various supercell models are constructed in order to reduce the strain induced by the lattice mismatch. The results show that stanene interacts overall weakly with graphene via van der Waals (vdW) interactions. Multiple phases of different cryst...

Dislocations are topological line defects in three-dimensional crystals. Same-sign dislocations repel according to Frank's rule |b1 + b2|(2) > |b1|(2) + |b2|(2). This rule is broken for dislocations in van der Waals (vdW) layers, which possess crystallographic Burgers vector as ordinary dislocations but feature "surface ripples" due to the ease of bending and weak vdW adhesion of the atomic lay...

Niikawa,N. 6739 Nishi.M. 6726 Niwa,O. 6709 Nixon.P. 6715 Noda.H. 6700 O'Hare.M.C. 6703 Okayama.H. 6485 Okazaki.K. 6485 Okazaki.N. 6485 Omura.T. 6700 Pakula.T.M. 6553 Pang,C.-P. 6731 Papaconstantinou.J. 6677 Pearce.J.H. 6713 PetruSyte.M. 6607 Polten,A. 6746 Pommier.Y. 6611 Pulleyblank.D.E. 6523 Puurand.U. 6694 Qiu,H. 6665 Rabek,J.P. 6677 Rafalski,J.A. 6531 RajBhandary,U.L. 6699 Rathgeber.G. 6633...