Materials Literature
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An investigation was undertaken to characterize the time progression of the Pt etch process during the dry etching (DE) of fence-free patterned structures. The goal of this study was to clarify the mechanism of fence-free Pt etching. In particular an explanation was sought that could account for the origin of the extr…
Abstract Oxisols contain stable aggregates, and sorption and desorption kinetics for aggregates typically are slower than for disaggregated samples. The objectives of this research were to determine whether aggregation inhibits Fe and Al extraction more in large than small aggregates, and to determine whether aggregat…
A macromodel for nonlinear devices exhibiting hysteresis is presented. Although this model is based on existing ideas of ferromagnetic hysteresis, it can be applied to all hysteresis phenomena by choosing suitable parameters. It consists only of four algebro-differential equations with ten parameters and exhibits all…
Atomistic simulation represents a valuable methodology for interpreting and predicting surface structures. The emphasis of our work is to develop and apply this approach to understanding the role of surface defects and additives in modifying the structure and stability of mineral surfaces. The basis of our approach is…
A new model of ferroelectric phase transitions in disordered crystals is developed. The model takes into account the nonequivalence of the structural environment of identical ions, which alters the balance of forces governing ferroelectric structural instability. In contrast with its predecessors, the new model can be…
Abstract Low‐molecular‐weight poly(ethylene oxide)‐polyalkane (PEO‐PA) diblock copolymers have been examined between the order‐disorder transition and PEO melting temperature using small‐angle neutron scattering (SANS), differential scanning calorimetry (DSC), and dynamic mechanical spectroscopy (DMS). Crystallization…
Transmission high‐energy electron holography has been utilized to quantitatively determine the magnitude, sign, and spatial extent of the electrical potential, electric field, as well as the charge and stress field distributions across electrically active grain boundaries (GBs) in polycrystalline SrTiO 3 . The polycry…
Properties of two-center Coulomb Sturmian basis sets are discussed. Analytic and numerical techniques to calculate these functions and coupling matrix elements are developed. A class of Sturmian functions is found that has no analytic continuation to negative energies and is not present in one-center potentials. Advan…
The various magnetic structures and magnetic phase transitions in the series ${\mathrm{Nd}}_{\mathrm{x}}$${\mathrm{Tb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{2}$${\mathrm{Ge}}_{2}$ have been thoroughly studied by means of macroscopic magnetic and thermal measurements (such as magnetization, ac initial m…
Abstract Various aniline derivatives carrying one or two alkyl substituents in various positions (alkylanilines, toluidines and xylidines) were polymerized electrochemically. The obtained conducting polymers were characterized by cyclic voltammetry, in situ infrared spectroscopy and in situ conductivity measurements.…
Arenicola marina possesses cuticular and interstitial collagens, which are mostly synthesised by its epidermis. A cDNA library was constructed from the body wall. This annelid cDNA library was screened with a sea-urchin-collagen cDNA probe, and several overlapping clones were isolated. Nucleotide sequencing of these c…
beta-Hydroperoxy alcohols 1-4 serve as effective tridentate oxygen donors for the highly diastereoselective, titanium-catalyzed epoxidation of ene diols 5a-e. Thus, in contrast to the bidentate tert-butyl hydroperoxide, the usual oxygen donor employed in Sharpless-type epoxidations and known to work poorly for polyhyd…
Abstract We report on the phase behavior and microdomain structure of two types of diblock copolymers containing a liquid crystal (LC) block joined to a flexible coil block. Consideration of the symmetry groups of the liquid crystalline phases and of the block copolymer microdomain structures provides a rationale for…
A novel highly anisotropic room-temperature process for silicon etching, using mixtures of SF6 and CHF3 gases is presented. The etch rate, selectivity, dc bias voltage and anisotropy as a function of the reactive ion etching conditions (mixture composition, pressure and rf power) are discussed. Excellent anisotropy co…
Magnetic excitations in tetranuclear clusters of exchange-coupled metal ions encapsulated by polyoxotungstate ligands (1) have been observed by inelastic neutron scattering (INS) in the salts K10[M4(H2O)2(PW9O34)2]·nH2O, where M2+ = Mn, Co, and Ni. INS provides a much deeper and more detailed insight into the nature o…
The miscibility of poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) with poly(butylene terephthalate) (PBT) has been studied by 13 C CP/MAS NMR complemented with DSC measurements. The blends were prepared by a solution precipitation method. The DSC examination shows that the T g of the blends is between the T g of t…
Pt catalysts supported on Al 2 O 3, CeO 2 /Al 2 O 3, Na 2 O/Al 2 O 3, and K 2 O/Al 2 O 3 were prepared and characterized with respect to surface area, CO chemisorption, temperature-programmed desorption (TPD) of CO 2, and temperature-programmed reduction (TPR) of H 2 . The effects of basic additives on Pt/Al 2 O 3 for…
Processing effects of wet ball‐milling on the microstructure and fracture strength of Al 2 O 3 /5 vol% SiC nanocomposites were investigated. Homogeneous microstructure and a high fracture strength of 1200 MPa could be achieved under the milling condition of relatively low wear contents of Al 2 O 3 grinding media, main…
A series of poly(thioarylene)s, including fluorinated poly(thioarylene)s, was prepared from cyclic disulfide oligomers and diiodo or dibromo aromatic compounds in diphenyl ether solution at 270 °C. The cyclic disulfide oligomers were derived from 4,4‘-thiobis(benzenethiol) and 4,4‘-biphenyldithiol, respectively. Diiod…
Two methods for producing Si-oxide barriers upon which crystalline Si layers can be grown are presented. One method entails oxide island nucleation on a clean vicinal Si(001) surface. The second method makes use of void formation in ultrathin oxides on the Si(100) surface at elevated temperatures. Either method result…