Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Perylene microcrystals with different sizes from about 50 nm to about 200 nm were prepared using the reprecipitation method. Their excitonic absorption peaks were found to shift to the high energy side with decreasing crystal size, that is to say, the shifts from that of the bulk crystal were about 500 cm -1 and 1420…
The spin gap energy (\ensuremath{\approx} 30 meV) associated with the low-spin ($S=0$) to high-spin ($S=2$) transition in LaCo${\mathrm{O}}_{3}$ was proved to be considerably smaller than the charge gap energy (\ensuremath{\approx} 0.1 eV) which was estimated by optical spectroscopy. Hole doping in the low-spin ground…
The powder diffraction method, by using conventional X-ray sources, was devised independently in 1916 by Debye and Scherrer in Germany and in 1917 by Hull in the United States. The technique developed steadily and, half a century later, the `traditional' applications, such as phase identification, the determination of…
A model for the viscosity of glass-forming molecular liquids is proposed in which a ``flow event'' requires a local volume increase. The activation energy for a flow event is identified with the work done in shoving aside the surrounding liquid; this work is proportional to the high-frequency shear modulus, which incr…
Using electron paramagnetic resonance, the motion of oxygen vacancies within the oxygen octahedron in perovskite BaTiO 3 is observed via the alignment of oxygen vacancyrelated defect dipoles induced by bias/heat combinations. The vacancy motion is found to have an activation energy of 0.91 eV, in excellent agreement w…
The temperature dependences of heat expansion, elastocaloric effect, magnetocaloric effect, and the shift in the critical temperature of the transition due to tensile stress have been measured using samples of the same concentration Fe49Rh51 in the antiferromagnetic-ferromagnetic (AF-F) transition range. Using data on…
The heat capacity and thermal expansion of ${\mathrm{SrZrO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ have been determined by drop calorimetry and energy-dispersive x-ray diffraction from 300 up to 1800 K or more. For both compounds, thermal history has a slight influence on relative enthalpies in the range 900--1400 K but a s…
Aspects of the ultrastructural interaction between collagen and mineral crystals in embryonic chick bone have been examined by the novel technique of high voltage electron microscopic tomography to obtain three-dimensional information concerning extracellular calcification in this tissue. Newly mineralizing osteoid al…
We have studied the temperature dependence of dielectric relaxation times in terms of the peak frequency fmax(T) of dielectric loss ε″(ω) and the dc-conductivity σdc(T) of several glass-forming liquids, covering 12 decades in the peak frequency fmax and 9 decades in σdc. Although dc-conductivity samples the mobility o…
Direct electrodeposition of zinc oxide films is reported for the first time. That this method of preparation is suited to large‐scale production could be important for applications of ZnO, e.g., in solar cells. In addition to a description of the preparation and properties of the films, it is shown that the morphology…
Results of a detailed investigation of the structure and electron-transport properties of ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathit{A}}_{\mathit{x}}$${\mathrm{MnO}}_{3}$ (A=Ca, Sr) over a wide range of compositions are presented along with those of parent ${\mathrm{LaMnO}}_{3}$ containing different…
A suitable relationship between the linear refractive index n0, the energy gap Eg, and the nonlinear refractive index n2 has been looked for on the basis of experimental and theoretical data reported in the literature for numerous simple oxides. It has been established that the nonlinear refractive index increases wit…
A mixed oxide (Zn1−xAlx)O exhibits promising thermoelectric properties attaining a dimensionless figure of merit ZT of 0.30 at 1000 °C, which value is much superior to other oxides and quite comparable to conventional state-of-the-art thermoelectric materials. The addition of a small amount of Al2O3 to ZnO results in…
The average electronic oxide polarizability α02− of numerous single component oxides has been calculated on the basis of two different properties: linear refractive index n0 and energy gap Eg, which have demonstrated remarkable correlation. The optical basicity Λ of the oxides has been estimated on the basis of averag…
We report high resolution electron microscope (HREM) observations and atomistic simulations of the bending of single and multi-walled carbon nanotubes under mechanical duress. Single and multiple kinks are observed at high bending angles. Their occurrence is quantitatively explained by the simulations, which use a rea…
Mechanical and processing properties of recycled polyvinylchloride (PVC, from bottles and pipes) were compared with those of virgin pipe grade PVC. Blends of recycled and pipe grade PVC were also prepared and characterized. It was found that the particle size and the restabilization of the recycled PVC are the two mai…
The simulation results based on the devulcanization model presented in Part I of this study are described for devulcanization of SBR vulcanizates. The vulcanizates are conveyed by a single-screw extruder to a thin gap between a stationary die and a vibrating horn. Gapwise velocity, temperature, and shear-rate distribu…
Tire and rubber waste recycling is an important issue facing the rubber industry. In addressing this issue, the present article describes the first attempt to formulate a model and to simulate a novel continuous ultrasonic devulcanization process. The proposed model is based upon a mechanism of rubber network breakup…
The present work is intended to investigate the thermopower and electrical conductivity studies of some substituted strontium W-type hexagonal ferrites as a function of composition and temperature. On the basis of the sign of the Seebeck coefficient (S), the ferrites under investigation have been classified as n-type…
We report measurements of the temperature and pressure dependence of ultrasonic modulus and specific volume in polystyrene between 50 and 280°C and applied pressures up to 775 bar. The volumetric glass transition temperature is found to vary linearly with pressure. Furthermore, it coincides with the temperature at whi…