Materials Literature
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Topography of silicon surfaces irradiated by a 2 MeV Si$^+$ ion beam at normal incidence and ion fluences in the range $10^{15}-10^{16}$ ions/cm$^{2}$ has been investigated using scanning tunneling microscopy. At length scales below $\sim$~50 nm, surface smoothing is observed; the smoothing is more prominent at smalle…
In this paper we present the results on Raman-active modes calculation in achiral $(n,n)$ and $(n,0)$ carbon nanotubes (CNTs). vibrational spectra are derived as the eigenvalues of corresponding dynamical matrix at the $Γ$-point of Brillouin zone. Diagonal components and $α_{xy} (=α_{yx})$ are the only non-zero compon…
The switching kinetics in ferroelectric thin films has been intensively studied during the past decade. It is widely accepted that this kinetics is basically governed by the dynamics of domain coalescence (the Kolmogorov-Avrami-Ishibashi model). This conclusion is mainly supported by fitting the time dependence of the…
In this paper, the average unit cell for a quasicrystal is constructed by a statistical approach. For the Penrose tiling, it is shown that such a unit cell is fully equivalent to the oblique projection of the atomic surface onto physical space. The obtained statistical distributions can be easily extended to imperfect…
The radio frequency (RF) plasma-modified surfaces of kaolinite were investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and deuteration techniques to determine the nature of RF plasma-induced surface functional groups, the altered sites in the lattice, and interaction mechanism between…
State of the art CASSCF and CASPT2 calculations have been performed to elucidate the nature of the electronic transitions observed in the experimental spectrum of the octacyanomolybdate(V) cation. Assuming a triangular dodecahedral structure for this complex gives a convincing agreement between theory and experiment.…
Crystalline modifications α and β of uniaxially oriented poly(tetramethylene naphthalate) [PTMN] sample have been found to show a reversible phase transition, which is induced by an application of a tensile force along the draw axis, as clarified by the measurement of polarized infrared spectra under tension. The tran…
The formation of vesicles during the synthesis of mesostructured surfactant-silicate materials has been evidenced for the first time by applying in situ Cryo-TEM. A mixture of anionic and cationic surfactants was used to fine-tune the packing parameter of the supramolecular surfactant assembly. It is shown that the ve…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSpherulite Morphology of Form III Isotactic Poly(1-butene)B. Lotz and A. ThierryView Author Information Institut Charles Sadron (CNRSULP), 6, rue Boussingault, 67083 Strasbourg, France Cite this: Macromolecules 2003, 36, 2, 286–290P…
The theoretical basics of the analysis of voids in crystal structures by means of Voronoi-Dirichlet polyhedra (VDP) and of the graph theory are stated. Topological relations are considered between VDPs and atomic domains in a crystal field. These relations allow the separation of two non-intersecting topological subsp…
Copper binding properties were investigated for several popular zwitterionic buffers. The two buffers 4-morpholinoethanesulfonic acid (MES) and 3-N-morpholinopropanesulfonic acid (MOPS) did not bind copper and would be good choices for metal speciation studies within their operational pH range. Conversely, 3-(N-morpho…
The buildup and secondary structure of poly( l -glutamic acid)/poly(allylamine) (PGA/PAH) multilayer films were investigated by means of optical waveguide lightmode spectroscopy, quartz crystal microbalance, and Fourier transform infrared spectroscopy in attenuated total reflection mode. The thickness and the mass of…
Hot Isostatic Pressing was applied to synthesize bulk samples with diameter up to 30 mm starting with Alfa Aesar magnesium diboride powder. HIPing at 2 kbar, 1000 C with cooling under pressure (DMCUP cycle) resulted in a fully dense (or low porosity) material with a sharp superconducting transition and critical curren…
In this study, transmission FT-IR spectroscopy is used to investigate the adsorption of water on aluminum oxide surfaces, including both single-crystal and particle surfaces. The FT-IR spectra of the (0001) surface of α-Al 2 O 3 single crystals at 296 K in the presence of 0.2 to 20 Torr H 2 O vapor pressure correspond…
Regular nets are defined as those with symmetry that requires the coordination figure to be a regular polygon or polyhedron. It is shown that this definition leads to five regular 3-periodic nets. There is also one quasiregular net with a quasiregular coordination figure. The natural tiling of a net and its associated…
Organic modification with aminopropyl group of two MCM-41 materials having different pore sizes (obtained from trimethylalkylammonium surfactants with different chain sizes (16 and 12 carbon atoms)) has been carried out in order to control the delivery rate of ibuprofen from the siliceous matrix. This functionalizatio…
The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble m…
A novel alcohol dehydrogenase enzyme has been cloned from the hyperthermophilic archaeon Aeropyrum pernix and overexpressed in Escherichia coli. This zinc-containing enzyme has been crystallized by the sitting-drop vapour-diffusion method using PEG 600 as precipitant. The crystals diffract to 1.5 A resolution and belo…
Reduced layered niobate RbNa x Ca 2 Nb 3 O 10 was synthesized via the reaction of RbCa 2 Nb 3 O 10 with sodium vapor at 500 °C. The structure has been refined from X-ray powder diffraction data, revealing that this black compound crystallizes in the space group P 4 2 / ncm with a = 5.4790(3) Å, c = 28.8264(9) Å, and Z…
Cholesterol-conjugated proteinoids and their aggregation behaviors were investigated with model proteinoid systems. Model proteinoids of molecular weights in the range of 4000 to 6000 were synthesized by anhydrous thermal condensation forming a matrix with glutamic acid and aspartic acid and of naturally occurring ami…