Materials Literature
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Strategies for single-walled carbon nanotube (SWNT) separation are critical to developing nanotubes as useful nanoscale building blocks. Herein, we demonstrate that solution-phase ozonolysis of SWNTs fosters diameter selectivity in SWNTs. The main conclusion of our work is that in this sidewall addition reaction, smal…
Abstract The surpassing of the solubility product of the anhydrous forms of calcium carbonate—calcite, aragonite, and vaterite—is not sufficient to induce spontaneous precipitation. The existence of a metastable zone, in the nucleation of the calcium carbonate, is still an experimental phenomenon. A thermodynamic dema…
The paper reports the enhanced photoluminescence of trivalent europium (Eu 3+ ) ions in the vicinity of nanometer-sized metal particles in glasses. In this study, gold (Au) colloids synthesized in solution were introduced into a borosilicate (B 2 O 3 −SiO 2 ) glass matrix together with Eu 3+ ions via a sol−gel route.…
The ZrO2-TiO2 phase diagram was studied with synthesis experiments between 1200°C and 1650°C, 1 atm and 28 kbar, investigating the effect of pressure on the compositions of rutile [TiO2], zirconia [ZrO2] , and zirconium titanate [(Zr,Ti)2O4) solid solut
The paper presents a detailed experimental and theoretical study of the four mixed nickel-bisdithiolene complexes [Ni(Pr(i)(2)pipdt)(dmit)] (1b, Pr(i)(2)pipdt = 1,4-diisopropyl-piperazine-3,2-dithione; dmit = 1,3-dithiolo-2-tione-4,5-dithiolato), [Ni(R(2)pipdt)(mnt)] (2b", R = 2-ethylhexyl; mnt = maleonitriledithiolat…
In this paper we present a new synthesis for N -alkylated 2,7-dibromocarbazoles, from which 2,7-linked carbazole trimers have been synthesized by Suzuki cross coupling. The compounds were characterized regarding their thermal, optical, and electrochemical properties and compared to analogous fluorene trimers, which al…
Theoretical calculations of electron energy-loss near-edge structure (ELNES) and x-ray absorption near-edge structure (XANES) of selected wide-gap materials including ${\text{TiO}}_{2}$, AlN, GaN, InN, ZnO, and their polymorphs are performed using a first-principles method. Calculations of 39 $K$ and ${L}_{3}({L}_{2,3…
Polyelectrolyte multilayers with alternating porous and fully dense regions have been assembled from poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and poly(sodium 4-styrenesulfonate) (SPS) in appropriate combinations. The porous zones were developed postassembly via immersion of the heterostructure f…
A self-consistent electronic structure calculation based on the Luttinger-Kohn model is performed on GaMnAs/GaAs multilayers. The Diluted Magnetic Semiconductor layers are assumed to be metallic and ferromagnetic. The high Mn concentration (considered as 5% in our calculation) makes it possible to assume the density o…
We present a new linear scaling method for the energy minimization step of semiempirical and first-principles Hartree-Fock and Kohn-Sham calculations. It is based on the self-consistent calculation of the optimum localized orbitals of any localization method of choice and on the use of orbital-specific basis sets. The…
A novel class of mesoporous aluminosilicate molecular sieves has been prepared by replication from carbon mesoporous molecular sieves (CMKs) using zeolite precursors and characterized by a variety of analytical and spectroscopic techniques, such as XRD, N 2 adsorption/desorption, SEM/TEM, IR, hyperpolarized (HP) 129 X…
It was hypothesized that nanoscale adhesion ligand spacing regulates cell adhesion, proliferation, and differentiation, and that this control can be decoupled from the overall ligand density. Alginate was chemically modified with a peptide containing the cell adhesion sequence arginine−glycine−aspartic acid (RGD), and…
We apply standard, first-principles calculations to a complete treatment of lattice dynamics in the harmonic approximation. The algorithm makes use of the straightforward ``frozen-phonon'' approach to the calculation of vibrational spectra and addresses some limitations of the method. Our prescription's validity is in…
We study the role of strong electron confinement in surface-enhanced Raman scattering from molecules adsorbed on small noble-metal particles. We describe a new source of Raman signal enhancement which originates from different behavior of sp-band and d-band electron densities near the particle boundary. In small parti…
We report the results of an x-ray scattering study that reveals oxidation kinetics and formation of a previously unreported crystalline phase of SnO at the liquid-vapour interface of Sn. Our experiments reveal that the pure liquid Sn surface does not react with molecular oxygen below an activation pressure of \~5.0*10…
We study inverted core/shell nanocrystals (NCs) in which a core of a wide gap semiconductor (ZnSe) is overcoated with a shell of a semiconductor of a narrower gap (CdSe). By monitoring radiative recombination lifetimes for a series of these NCs with a fixed core radius and progressively increasing shell thickness, we…
The structure and dynamics of poly(amido amide) (PAMAM) dendrimers have been of great interest both scientifically and industrially, but such important features as the distributions of atoms, channels, and strain inside these molecules remain unresolved. This paper reports results from systematic investigations of the…
Die komplexe Molekülstruktur des ionischen Clusters [Ag26In18S36Cl6(dppm)10(thf)4]2+[InCl4(thf)−]2 (siehe Bild) wurde sowohl mithilfe theoretischer Methoden (Dichtefunktionaltheorie) als auch experimentell (Einkristallröntgenbeugung, FT-Massenspektrometrie) bestimmt. Der Cluster entstand bei der Umsetzung von AgOOCPh…
Abstract We have prepared four new octaaminoamide resorcin[4]arenes having hydrocarbon chains of different lengths ( 1 , 2 : R = CH 3 ; 3 , 4 : R = C 11 H 23 ) and different terminal groups ( 1 , 3 : NH 2 ; 2 , 4 : NMe 2 ). The surface tension and self‐assembly of aqueous solutions of 2 − 4 were studied and their crit…
Abstract Summary: In a series of papers the crystallization of a commercial polyethylene (PE) material has been studied by in situ ultra small‐angle X‐ray scattering (USAXS) and it has been found that the placement of crystallites is predominantly a random car parking process, dealt with in the field of random sequent…