Materials Literature
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The spectral and geometric trends of Ln(trensal) complexes (H(3)trensal = 2,2',2' '-tris(salicylideneimino)triethylamine) along the lanthanide series are analyzed. Low-temperature polarized absorption and luminescence spectra are reported for nine of the complexes with transitions suitable for analysis. Both the angul…
The synthetic route to a new fully conjugated phenanthroline appended phthalocyanine is described. This compound has been fully characterised by elemental analysis, UV-VIS, IR, MS and 1H NMR spectroscopy.
We predict that freely suspended, linear molecular conductors or dielectrics, such as carbon nanotubes, can support electronic states that are localized far from the surface. These "tubular image states" are formed in extended potential wells resulting from the tug of war between the external electron's attraction to…
A copper(II) Schiff base complex bearing hydroxyl groups [bis(4-hydroxysalicylaldehyde)ethylenediaminate] copper(II), [Cu(4-HOsalen)], was directly anchored onto an air-oxidized activated carbon. Oxidation of the activated carbon was done with a mixture of air and N 2 (with 5% O 2 ) to increase the oxygenated surface…
We use the spectral moments method in the framework of the bond-polarization theory to calculate polarized nonresonant Raman spectra of chiral and achiral single-wall carbon nanotubes as a function of their diameter and length. In a previous approach, an investigation of finite-size effects was limited to a narrow len…
Wool is a complex material, composed of cuticle and epicuticle cells, surrounded by a cell membrane complex. Wool fibers absorb moisture from air, and, once immersed in water, they take up considerable amounts of liquid. The water absorbency parameter can be determined from weight gain, according to a standard method,…
This brief review critically assesses achievements, current trends, limitations, and prospects for crystal engineering with an emphasis on the growth opportunities for this field.
A new approach to the preparation of epoxy−clay nanocomposites is reported based on the intercalation and exfoliation of homostructured mixed inorganic/organic cation exchanged forms of a commercially available montmorillonite (PGW) and a synthetic fluorohectorite (FH) clay. In these mixed-ion homostructures both the…
In this study, two series of the polyimide−silica hybrid optical thin films, PMDA−ODA/SiO 2 and 6FDA−ODA/SiO 2, were synthesized using an in situ sol−gel reaction combined with spin coating and multistep curing. The hybrid thin films were prepared by the aminoalkoxysilane-capped poly(amic acid)s and tetramethoxysilane…
We show that the electronic and atomic structure of carbon nanotubes undergo dramatic changes with hydrogen chemisorption from first principle calculations. Upon uniform exohydrogenation at half coverage, the cross sections of zigzag nanotubes become literally square or rectangular, and they are metallic with very hig…
We consider a magnet with uniaxial anisotropy in an external magnetic field along the anisotropy direction, but with a field magnitude smaller than the coercive field. There are three representative magnetization configurations corresponding to three extrema of the free energy. The equilibrium and metastable configura…
We describe the design and current performance of the high-flux backscattering spectrometer located at the NIST Center for Neutron Research. The design incorporates several state-of-the-art neutron optical devices to achieve the highest flux on sample possible while maintaining an energy resolution of less than 1mueV.…
Neutron Compton scattering measurements presented here of the momentum distribution of hydrogen in KH2PO4 just above and well below the ferroelectric transition temperature are sufficiently sensitive to show clearly that the proton is coherent over both sites in the high temperature phase, a result that invalidates th…
The effect of disorder on transport and magnetization in ferromagnetic III-V semiconductors, in particular (Ga,Mn)As, is studied theoretically. We show that Coulomb-induced correlations of the defect positions are crucial for the transport and magnetic properties of these highly compensated materials. We employ Monte…
Nanoscale structure formation in copolymers of polyethylene (PE) and polyhedral oligomeric silsesquioxane (POSS) with norbornene and cyclopentyl side-groups can be controlled through choice of crystallization conditions. Aggregates of both crystalline PE and crystalline POSS are found when crystallized from the melt.…
We present an all-electron implementation of the $\mathrm{GW}$ approximation and apply it to wurtzite ZnO. Eigenfunctions computed in the local-density approximation (LDA) by the full-potential linearized augmented-plane-wave or the linearized muffin-tin-orbital method supply the input for generating the Green functio…
Results of d.c. electric conductivity and Seebeck coefficient measurements for PFN, PFN+Li ceramic samples and PFN single crystals are presented. Marked influence of doping with lithium on the value of electric conductivity, and on the type of electric conductance has been found.
We examined in this work the effect of the inter-grains distributions as well as the scaling of the complex impedance in order to analyze its frequency dependance for composite metal-insulator films. The dependance of the characteristic frequencies on the inter-grain distribution is shown for large sample sizes. The i…
A convenient preparation is reported for a series of functionalized, thiol-stabilized gold particles with subnanometer core diameters ( d CORE = 0.8 ± 0.2 nm). The preparation produces previously inaccessible materials through ligand exchange reactions of a phosphine-stabilized precursor, Au 11 (PPh 3 ) 8 Cl 3, with ω…
Poly(ε-caprolactone)/clay nanocomposites were prepared by in-situ ring-opening polymerization of ε-caprolactone by using dibutyltin dimethoxide as an initiator/catalyst. A nonmodified Na + −montmorillonite and two montmorillonites surface-modified by dimethyl 2-ethylhexyl (hydrogenated tallow alkyl) and methyl bis(2-h…