Materials Literature
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Abstract Thermal degradation mechanisms of the copolymers of styrene (St) with methacrylonitrile (MAN) and α‐methylstyrene (αMSt) were studied by pyrolysis gas chromatography (Py‐GC) and thermogravimetry (TG). Thermal degradation of vinyl polymers in flash pyrolysis proceeded mainly in the competition between depolyme…
Abstract A series of liquid crystalline copolyesters containing both horizontal and lateral rods in main chain were synthesized through solution polymerization of 2,5‐bis(4‐alkoxy benzoyloxy)hydroquinone, 4,4 ′‐dihydroxy‐α,ω‐diphenoxydecane and 4,4 ′‐dichloroformyl‐α,ω‐diphenoxydecane. These copolyesters were soluble…
The dielectric response has been studied in 10-μm-thick, single-crystal potassium tantalate films formed by crystal ion slicing. Scanning microwave microscopy shows that the implanted, pre-etched samples exhibit a bulk-like permittivity and low-loss tangent (0.0009) at 1.7 GHz. The separated free-standing films have s…
An improved oscillating drop method was developed to measure the surface tension and viscosity of a liquid without any external forces under microgravity conditions. The combination of a drop levitation system, a laser backlight system, and a line sensor enables the properties to be measured precisely. The surface ten…
Abstract Poly( L ‐lactide)–poly(ethylene glycol) (PLA–PEG) multiblock copolymers with predetermined short blocks ( M n ≤ 3000) were synthesized by polyesterification of PLA diols with PEG diacids in the presence of dicyclohexycarbodiimide and dimethylamide pyridine. The molecular structure and morphological features o…
An amorphous Ta(O,C)x layer was found to form at the TaC/Cu interface in the Si/TaC/Cu metallization system. The formation of the layer was induced by oxygen trapped in the as-deposited films, since on the basis of thermodynamic evaluation of the ternary Ta–C–O system, the dissociation of the TaC layer and the formati…
The noise properties at room temperature of multiwalled carbon nanotubes under forward bias, for frequencies between 10 Hz–10 kHz, have been investigated. The noise measurements were made for one individual multiwalled carbon nanotube (1 MW) and two crossing multiwalled carbon nanotubes (2 CMW). The excess noise found…
Domain switching behavior of 0.955Pb(Zn1/3Nb2/3)O3–0.045PbTiO3 ferroelectric single crystal has been investigated using the ultrasonic technique in addition to the polarization hysteresis measurements. The ultrasonic technique makes it possible to extend the coercive field measurement to frequencies as low as 10−5 Hz,…
Persistent ferromagnetic magnetization (M) as large as 0.6 μB per Mn site can be induced by irradiating visible laser pulses on a thin film of 1% Cr-doped Pr0.5Ca0.5MnO3. The enhancement of M upon the photoexcitation was also confirmed by the scanning superconducting quantum interference device microscope as an increa…
Shubnikov--de Haas (SdH) oscillations have been examined for organic conductors $\ensuremath{\lambda}\ensuremath{-}(\mathrm{BETS}{)}_{2}{\mathrm{Fe}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Cl}}_{4}$ $(x=0,$ 0.45, 0.78, and 1.0). In spite of the variety of the magnetic phases, no significant difference is found in…
After bipolar electric fatigue of bulk lead–zirconate–titanate ceramics, the well known reduced remnant polarization values are observed as well as an asymmetric strain hysteresis reflecting a macroscopic offset polarization. Thermal treatment and high electric fields each liberate the domain system from the microscop…
We have studied the dependence of magnetic properties on the carrier concentration of IV–VI diluted magnetic semiconductor Ge1−xMnxTe prepared by ionized-cluster beam technique. With increasing carrier concentration, the magnetic properties drastically change; saturation magnetization increases and coercive field decr…
High resolution He diffraction and scanning tunneling microscopy images of the fivefold surface of a single-grain i-AlPdMn quasicrystal are obtained showing an almost perfect quasicrystal order. Observed configurations can be identified within the framework of polyhedral models. The terrace terminations are found to b…
Abstract The reaction of toluene diisocyanate (TDI) with dimethylol propionic acid (DMPA) or diaminopentane sulphonic acid sodium salt (ES‐200) and other additives to form the structure of anionic polyurethane (PU) ionomer molecule has been proven by FT‐IR spectroscopy. In aqueous solution, the surface tension of anio…
Abstract A series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method. The polymerization processes were traced through IR techniques; results for the morphology and miscibility among mult…
Abstract Polymer degradation in solution has several advantages over melt pyrolysis. The degradation of low‐density polyethylene (LDPE) occurs at much lower temperatures in solution (280–360°C) than in conventional melt pyrolysis (400–450°C). The thermal degradation kinetics of LDPE in solution was investigated in thi…
$\ensuremath{\lambda}\ensuremath{-}(\mathrm{BETS}{)}_{2}{\mathrm{FeCl}}_{4}$ undergoes transitions from an antiferromagnetic insulator to a metal and then to a superconductor as a magnetic field is increased. We use a Hubbard-Kondo model to clarify the role of the ${\mathrm{Fe}}^{3+}$ magnetic ions in these phase tran…
Branchy alumina nanotubes (bANTs) have been shown to exist in aluminum oxide. Electron-beam evaporated 400 nm Al film on Si substrate is stepwise anodized in dilute sulfuric acid under the constant dc voltage 40 V at 10.0 °C. This electrochemical-anodizing route resulted in the formation of individual bANTs. Transmiss…
Bimodal (4 and 8 nm) mesoporous silicas with interconnected three-dimensional structure were synthesized by mild-temperature post-synthesis hydrothermal treatment of MCM-41 mesoporous materials in ammonia solution.
Epitaxially twinned (001)- , (118)- , and (104)-oriented La-substituted Bi4Ti3O12 (BLT) ferroelectric films have been grown by pulsed laser deposition on (001)- , (011)- , and (111)-oriented SrTiO3 single-crystal substrates, respectively, covered with SrRuO3. Well-defined (001)-oriented BLT films were grown at a subst…