Materials Literature
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We present a state-of-the-art first-principles analysis of electronic transport in a Pt nanocontact in the presence of H2 which has been recently reported by Smit et al. in Nature 419, 906 (2002). Our results indicate that at the last stages of the breaking of the Pt nanocontact two basic forms of bridge involving H c…
Carbon nanotubes and biological filaments each spontaneously assemble into kinked helices, rings, and "tennis racket" shapes due to competition between elastic and interfacial effects. We show that the slender geometry is a more important determinant of the morphology than any molecular details. Our mesoscopic continu…
A two-dimensional lattice model with bond disorder is used to investigate the fracture behaviour under stress-controlled conditions. Although the cumulative energy of precursors does not diverge at the critical point, its derivative with respect to the control parameter (reduced stress) exhibits a singular behaviour.…
Abstract Drilling into a hydrogen-sulphide (H2S) rich formation presents risks that the highly toxic gas might be carried to the surface and released, thus creating a serious hazard. To mitigate this risk, it is standard practice to run the drilling mud at high pH and to include a sulphide scavenger. Commonly, such sc…
The possibility for double-wall carbon nanotube to operate as the bolt and nut pair is studied. The barriers for relative motions of walls along the helical "thread" line and for jumps on neighbour helical lines are calculated as functions of wall lengths for the set of double-wall carbon nanotubes. The dynamics of re…
The incommensurate, modulated crystal structures of Sr 1+ x (Co x Mn 1 - x )O 3 ( x ≈ 0.266 and 0.280) have been refined by a (3+1)D superspace profile analysis of neutron powder diffraction data. The structures are related to the 2H perovskite structure and consist of two subsystems, [Co x Mn 1 - x O 3 ] ∞ chains con…
Triethylenetetramine (L(4)) was used as a tetradentate blocking ligand that, after complexation with Ni(II), leaves two sites ready for ligation with tricyanomethanide. The formed binuclear complex [L(4)Ni(NCC(CN)CN)(2)NiL(4)](ClO(4))(2) exhibits a ferromagnetic coupling with J/hc = +0.15 cm(-1) and g(Ni) = 2.126; bel…
A tripodal ligand, tris(2-pyridyl)carbinol, affords a novel tetradentate coordination mode in homodinuclear lanthanide complexes, which exhibit remarkably short distances between metal ions. The strong luminescences of Eu(III) and Tb(III) complexes with the ligand demonstrate that the ligand has a suitable excited sta…
The reaction of MnF(3) with 5,6-dimethylbenzotriazole (Me(2)BTAH) gives the [Mn(III)(8)] complex [Mn(8)O(4)(OMe)(2)(Me(2)BTA)(6)F(8)(Me(2)BTAH)(MeOH)(8)] and the [Mn(IV)(3)Mn(III)(10)] complex [Mn(13)O(12)(Me(2)BTA)(12)F(6)(MeOH)(10)(H(2)O)(2)]. The octametallic species is an "intermediate" in the formation of the tri…
Several intermediates and final products of the reactions of [Rh(2)(mu-CH(3)COO)(4)(CH(3)OH)(2)] with a tridentate ligand bis(2-pyridylmethyl)amine (bpa) and bidentate 2-(aminomethyl)pyridine (amp) have been isolated, and the chelation processes of these ligands to the dirhodium(II) center are discussed. The reaction…
The hydrothermal transformation at 90−95 °C of a slurry of Al 2 O 3 /MgO/(CH 3 COOH)/H 2 O with molar oxide composition 1:4.4:2.2:1111 produced a hydrotalcite-like (HT) material free from phase impurities and having an approximate unit cell composition of Mg 0.66 Al 0.33 (OH) 2 (CHCOO) 0.33 . 13 C NMR and 27 Al NMR sp…
The synthesis and magnetic properties are reported of two new clusters [Mn(10)O(4)(OH)(2)(O(2)CMe)(8)(hmp)(8)](ClO(4))(4) (1) and [Mn(7)(OH)(3)(hmp)(9)Cl(3)](Cl)(ClO(4)) (2). Complex 1 was prepared by treatment of [Mn(3)O(O(2)CMe)(6)(py)(3)](ClO(4)) with 2-(hydroxymethyl)pyridine (hmpH) in CH(2)Cl(2), whereas 2 was ob…
A new family of spin crossover complexes, [Fe(II)H(3)L(Me)](NO(3))(2).1.5H(2)O (1), [Fe(III)L(Me)].3.5H(2)O (2), [Fe(II)H(3)L(Me)][Fe(II)L(Me)]NO(3) (3), and [Fe(II)H(3)L(Me)][Fe(III)L(Me)](NO(3))(2) (4), has been synthesized and characterized, where H(3)L(Me) denotes a hexadentate N(6) tripod ligand containing three…
The development of surface-enhanced Raman scattering (SERS)-active substrates for cancer gene detection is described. The detection method uses Raman active dye-labeled DNA gene probes, self-assembled monolayers, and nanostructured metallic substrates as SERS-active platforms. The mercaptohexane-labeled single-strande…
In a Comment (cond-mat/0310030) on our recent paper on network glasses (Phys. Rev. Lett., 2003, 90, 085505), Micoulaut and Boolchand (MB) compare our predictions on glass transitions in network systems for the ratios of the transition temperatures TA/TG and TK/TG with experimental data. They claim significant differen…
The crystal structure of the α-form of poly( l -lactide) was analyzed by the linked-atom least-squares refinements for the X-ray fiber diffraction data. The space group was orthorhombic P 2 1 2 1 2 1, and the unit cell contained the antiparallel two chains. The chain conformation was the 2-fold s(15*2/7) helix distort…
Carbon nanotubes (CNT) have recently emerged as a promising class of electron field emitters. They have a low threshold electric field for emission and a high emission current density which make them attractive for technological applications. In this article we review recent progress on understanding of CNT field emit…
Mechanical properties of carbon nanotubes are discussed based on recent advances in both modeling and experiment.
Low-temperature excitation has been investigated for polycrystals of ordered double-perovskite alloys ${\mathrm{Sr}}_{2}\mathrm{Fe}({\mathrm{Mo}}_{1\ensuremath{-}y}{\mathrm{W}}_{y}){\mathrm{O}}_{6}$ $(0<~y<~1)$ by specific-heat measurements. Critical enhancement of excess low-temperature specific heat with anoma…
La 0.67 Sr 0.33 MnO 3 ( LSMO ) thin films were grown onto CaMnO3(CMO) buffered SrTiO3(100) by pulsed laser deposition. Because of the in-plane compressive strain induced by the lattice mismatch between CMO and LSMO, a perpendicular magnetic anisotropy (PMA) was obtained in the overlayer LSMO. Using the magnetic force…