Materials Literature
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Abstract Silica in combination with organosilanes ( e.g. [bis(3-triethoxysilylpropyl)tetrasulfane] = TESPT) has recently become more important in tire applications. Their use in tire treads leads to an improvement in rolling resistance and wet traction. The requirements for the attainment of these properties are, that…
A mechanism that is simpler than the recently advanced is followed for the (salen)Mn-catalyzed asymmetric epoxidation of olefins. Oxametallacycles such as B or B′ are not viable intermediates; radical species such as A, which are directly formed by attack of the olefin on the oxomanganese catalyst are more likely cand…
The effect of elemental substitutions on the properties of the ferromagnetic, conducting, highly magnetoresistive compound ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ has been studied. The results of Co doping and Ni doping on the Mn site and Gd doping on the La site are reported. These compounds were i…
We report electrical transport experiments on the colossal magnetoresistance compound $({\mathrm{L}\mathrm{a},\mathrm{C}\mathrm{a})\mathrm{M}\mathrm{n}\mathrm{O}}_{3}$ over a wide range of composition and temperature. Comparison of thermopower and electrical resistivity measurements above the metal-insulator transitio…
A short overview is given on deposition and integration of PZT thin films on silicon for MEMS applications. The application principles are explained and the piezoelectric coefficients are compared with the ones of AlN and ZnO. The Materials figure of merits are given for various applications and discussed. The couplin…
The formation mechanism of the core-shell structure of a BaTiO 3 (BT)–MgO–Ho 2 O 3 -based system was studied. Mg reacted with BT at low temperatures and showed poor diffusivity compared with Ho. The core-shell structure was considered to be formed by the suppression of the diffusion of Ho into the core region by Mg. A…
The mode coupling theory (MCT) for the ideal liquid glass transition, which was worked out for simple liquids mainly by G\"otze, Sj\"ogren, and their co-workers, is extended to a molecular liquid of linear and rigid molecules. By use of the projection formalism of Zwanzig and Mori an equation of motion is derived for…
The damage caused to amphiphilic n -alkane monolayers under XPS measurement conditions was assessed in a combined XPS-FTIR study supplemented by additional AFM imaging and contact angle measurements. Nine different self-assembled monolayer/substrate systems were examined, comprising a long chain silane (C 18, OTS), a…
Various geometry optimization techniques are systematically investigated. The rational function (RF) and direct inversion in the iterative subspace (DIIS) methods are compared and optimized for the purpose of geometry optimization. Various step restriction and line search procedures are tested. The model Hessian recen…
Large piezoelectric single crystals of the Pb[(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 ]O 3 (PZN-PT) binary system have been successfully obtained using a conventional flux method and a suitable ratio of PZN-PT: PbO flux. The largest crystal had dimensions of 43×42×40 mm and weighed 415 g. In order to improve growth behavior and…
Abstract Electrospray mass spectrometry (ESI‐MS) is used to analyze in detail the structure of the first five generations of the poly(propylene imine) dendrimers with 4–64 end groups. Although the reaction sequence to prepare these dendrimers is highly optimized, an accumulation of statistical defects is observed at h…
The structural determination of a dinuclear Gd(III)−Ni(II) entity confirms the strict dinuclearity of the complex while the magnetic properties evidence the presence of a ferromagnetic interaction between the paramagnetic (S = 1) nickel ion and the gadolinium center (S = 7/2), with a J value of 3.6 cm-1.
Symmetrically substituted octahydroxy porphyrins, tetrakis(3‘,5‘-dihydroxyphenyl)porphyrin, H 2 T(3‘,5‘-DHP)P, tetrakis(2‘,6‘-dihydroxyphenyl)porphyrin, H 2 T(2‘,6‘-DHP)P, and their Zn(II) and Mn(III) derivatives have been developed as building blocks for supramolecular hydrogen-bonded networks. The crystal structures…
A family of silica molecular sieves with lamellar frameworks and hierarchical structure (denoted MSU-V) was assembled from homogeneous solutions of neutral H 2 N(CH 2 ) n NH 2 bolaamphiphiles ( n = 12−22) as the structure directors and tetraethylorthosilicate as the inorganic precursor. Optimal lamellar order was obse…
The mechanical and structural properties of the tetrahedral amorphous carbon (ta-C) films deposited by the filtered cathodic vacuum arc technique on silicon at room temperature have been studied over the carbon ion energy range 15–200 eV. High (about 80% or higher) sp3 bond fractions were obtained for almost all ion e…
Bismuth sodium titanate, (Bi 1/2 Na 1/2 )TiO 3 (BNT)-based solid solution, (1- x )(Bi 1/2 Na 1/2 )TiO 3 – x 1/2(Bi 2 O 3 ·Sc 2 O 3 ) [BNST-100 x ], was studied in order to determine its dielectric, ferroelectric and piezoelectric properties as a new group of lead-free piezoelectric ceramics. Measurements of dielectric…
Abstract Data are presented from tests of the stress relaxation response of a polycarbonate under torsional deformations. Tests were performed on samples over a range of strains from 0.0025 to 0.08, temperatures from 30 to 135°C and aging times from 1800 to 64,800 s. Individual data sets at each strain, temperature an…
We report a structural evolution analysis of the long-range and local order and disorder of lead scandium niobate (PSN) down to 10 K, using a combination of neutron and x-ray diffraction on powder and single crystals. The structure of PSN is discussed and compared with those of simple perovskite compounds and . In PSN…
Crystal orientation dependence of piezoelectric properties has been calculated phenomenologically for lead zirconate titanate (PZT) in the three-dimensional space. The calculation has been made for tetragonal PZT 40/60 (40% PZ and 60% PT) and rhombohedral PZT 60/40 compositions. The maximum longitudinal piezoelectric…
Electrospray mass spectroscopy has finally provided proof for the formation of oxomanganese(v) complexes such as 1 under the conditions of the Kochi-Jacobson-Katsuki epoxidation. Collision of 1 with olefins or sulfides in the gas phase regenerates the initial (salen)MNIII complexes by transfer of the oxygen atom.