Materials Literature
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Two cardiotonic glycosides were isolated from Calotropois procera; one of them (1) is a new natural product. Their structures were elucidated by extensive application of one- and two-dimensional 1H and 13C NMR spectroscopy. Copyright © 1999 John Wiley & Sons, Ltd.
Anomalous lattice properties and structural phase transition of NaV 2 O 5 have been studied under hydrostatic high pressure at room temperature by using powder X-ray diffraction techniques. Upon compression the c -axis along the stacking direction of V 2 O 5 -layers contracts rapidly and the b -axis along the one-dime…
Les masses volumiques ρ(θ) de maltitol, glucose et sorbitol ont été mesurées par pycnométrie et par dilatométrie. Les variations de la masse volumique en fonction de la température sont linéaires dans la phase liquide et dans l'état vitreux. La viscosité de cisaillement a été mesurée sur 11 décades, par trois techniqu…
The oxidation of SiC whiskers, contained in alkoxide‐derived mullite‐based matrices and exposed in air at 1000–1350°C for up to 1000 h, has been studied by analytical TEM, high‐resolution SEM, and XRD. Silicon carbide whiskers were effectively protected from oxidation when embedded in a pure mullite matrix, but oxidiz…
The phase behavior of the system water/SephadexG25 in a wide range of water content Wc (g water/g dry Sephadex) has been investigated by differential scanning calorimetry. At low degree of hydration (Wc < 0.38), the system is homogeneous and is characterized by a glass transition whose temperature-composition dependen…
Hellgelbe Einkristalle von (Hg2)2P2O7 sind über chemischen Transport im Temperaturgradienten (500 °C → 450 °C, 23 d) mit Hg2Cl2 als Transportmittel zugänglich. Charakteristisch für die Kristallstruktur (P2/n, Z = 2, a = 9,186(1), b = 4,902(1), c = 9,484(1) Å, β = 98,82(2)°, 1228 symmetrieunabhängige von 5004 Reflexen,…
In this study, we developed a simple electromechanical, lumped parameter model to simulate the dynamic performance of a deformable mirror driven by electrostrictive actuators in an adaptive optics system. Positioned behind the mirror, the multilayered actuator array dynamically controls the mirror's surface shape for…
A pseudobinary thermodynamic analysis of the alumina/copper–oxygen eutectic bonding process yields a value of approximately 1076°C for the invariant temperature of the {Cu( ss ), Cu( L1 ), CuAlO 2 , Al 2 O 3 } equilibrium. This temperature, which is 11°C above the eutectic, corresponds to a critical temperature for st…
Vanadium dioxide (VO2) thin films deposited on (1010) sapphire are composed of two mixed monoclinic phases, namely M1 and M2. The M1 phase is unstable because of the existence of a larger misfit strain in the (102) VO2 film. The reduction of misfit strain in the film favours the formation of the M2 phase. The X-ray di…
A stable solution chemistry and a consistent thermal processing route have been developed to produce multi-layer sol-gel lead zirconate titanate (PZT) piezoelectric coatings of high electrical quality. Up to 5 μm thick fully perovskite and piezoelectrically active crack-free coatings with permittivity of 1100–1300 and…
The photo-driven LC cell was assembled by sandwiching the liquid crystal material between two quartz or ITO plates covered with a 'command layer', which was fabricated from azobenzene-grafted ladder-like polysilsesquioxanes. The improved response sensitivity of the photo-driven cell, which means a lower threshold driv…
The temperature and compositional dependences of the electrical conductivity of semiconducting calcium vanadate glasses have been reported in the temperature range 80-500 K. It has been observed that the multiphonon assisted hopping model of small polarons in the nonadiabatic regime, which considers the strong interac…
By means of the surface impedance applicable to a finite film thickness, the conductor loss of a transmission line is investigated. It is found that there exists an optimum conductor thickness at which the conductor loss becomes a minimum. This thickness is predicted to be π/2 of the skin depth. Next, by using the thi…
Changes in the residual curvature and residual shear strain of eight cotton fabrics after cellulase treatment are compared with those of a polyester staple fabric after alkali treatment. The residual curvature of the cottons decreases less than that of the polyester, and the residual shear strain in the weft measureme…
A simplified model system containing amorphous glucose and glycine was analyzed in a differential scanning calorimeter (DSC) under air flow, nitrogen flow and in hermetically-sealed steel pans in order to study the effects of environmental conditions on its thennal behavior. DSC under nitrogen flow in open pans was ch…
The magnetic properties of the intermetallic compounds Gd 1− x Y x Mn 2 Ge 2 (0≤ x ≤0.5) (tetragonal crystal structure of the type ThCr 2 Ge 2 ) have been measured in fields up to 40 T in the temperature range 4.2–120 K on free powders (whose particles are free to rotate in a magnetic field), fixed powders, and polycr…
Abstract New oxomolybdenum(V) porphyrin complexes, [MoO(tmp)(C6H5SO3)] 1, [MoO(tpp)(C6H5SO3)] 2, [MoO(tpp)(HSO4)] 3, [{MoO(tpp)}2(μ-SO4)] 4, and [MoO(tpp)(NO3)] 5, were synthesized and characterized by UV-vis, IR, FAB-MS, and ESR measurements. The structures of the complexes, 1, 4, and 5, were determined by X-ray crys…
The Cantor−Leibler theory of macroscopic emulsion stabilization by adding diblock copolymer is reexamined with regard for the curvature of the equilibrium droplets. The treatment is based on the assumption that the equilibrium state of the system corresponds to adsorption of most diblock copolymer molecules at the int…
Abstract New alternating poly(amide‐ester)s derived from β‐hydroxy acids and α‐amino acids 3a,b or ϵ‐aminocaproic acid 4a‐c were prepared. Two approaches were considered: (i) polycondensation of N‐(β‐hydroxyacyl)‐amino acids 1a,b and 2b,c and (ii) ring‐opening polymerization of cyclic amide‐esters 5a‐c and 6a‐c . For…
Self-reinforced silicon nitride ceramics rely the generation of elongated grains that act as reinforcing elements to gain increases in fracture toughness. However, the size and number of the reinforcing grains must be controlled, along with the matrix grain size, to optimize the fracture toughness and strength. Furthe…