Materials Literature
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A review is given on the basic properties of 2:14:1 hard magnetic phases as well as technological procedures used for manufacturing R-Fe-B and R-Fe-C permanent magnets. First, we analyse the phase diagrams, crystal structure of hard magnetic phases and composition ranges in which these phases form solid solutions, as…
We describe a tellurite-based Er/sup 3+/-doped fiber amplifier (EDFA) with a flat amplification bandwidth of 76 nm and a noise figure of less than 7 dB. Furthermore, a parallel-type amplifier composed of this EDFA and a 1.45-μm-band Tm/sup 3+/-doped fluoride fiber amplifier achieved a flat amplification bandwidth of 1…
The crystalline swelling properties and interlayer structure of a cesium montmorillonite clay were investigated using molecular computer simulations. Two classes of dry-clay structures, proposed previously to explain X-ray diffraction and NMR experiments, were identified using Monte Carlo annealing calculations. Hydra…
During rapid solidification, solute may be incorporated into the solid phase at a concentration significantly different from that predicted by equilibrium thermodynamics. This process, known as solute trapping, leads to a progressive reduction in the concentration change across the interface as the solidification rate…
The synthesis of tailored nanoparticles—non-porous and porous—is a major challenge in advanced materials science. The authors here report the synthesis of submicrometer-size silica particles with a solid core and a thin porous shell (see Figure). The thermal stability and the high specific surface area make these sili…
To compare the heat responses of mechanically sensitive and mechanically insensitive A-fiber nociceptors, an electrical search technique was used to locate the receptive fields of 156 A-fibers that innervated the hairy skin in the anesthetized monkey (77 A beta-fibers, 79 A delta-fibers). Two-thirds of these afferents…
Summary Organic acids have been implicated in many soil‐forming and rhizosphere processes, but their fate in soil is poorly understood. We examined the sorption of four simple short‐chain organic acids (citric, oxalic, malic and acetic) in five acid soils and on synthetic iron hydroxide (ferrihydrite). The results for…
Amorphous precipitates of CaCO3 were prepared by reacting a mixed solution of Na2CO3–NaOH with a CaCl2 solution at various pH (≥11.2) at an ambient temperature of 278 K. The precipitates prepared at pH ranging from 11.2 to 13.0 were identified as amorphous calcium carbonate (ACC) by means of TG–DTA, FT-IR spectroscopy…
Intermediate Temperature Solid Oxide Fuel Cells Using a New LaGaO3 Based Oxide Ion Conductor: I. Doped SmCoO3 as a New Cathode Material, Ishihara, Tatsumi, Honda, Miho, Shibayama, Takaaki, Minami, Hiroaki, Nishiguchi, Hiroyasu, Takita, Yusaku
The shape-memory effect is a solid state phenomenon which exploits a reversible phase transformation to repeatedly achieve an initial shape, even after some deformation of the material. Numerous metal alloys exhibit this effect. One of the most widely used shape-memory alloys is TiNi, due to its large range of recover…
To investigate the metabolic link between fatty acid de novo synthesis and polyhydroxyalkanoic acid (PHA) synthesis, we isolated mutants of Pseudomonas putida KT2440 deficient in this metabolic route. The gene phaG was cloned by phenotypic complementation of these mutants; it encoded a protein of 295 amino acids with…
Porous thin-film dielectric insulators with significantly lower dielectric constants are expected to have great impact on the fabrication of ever smaller semiconductor devices and chips with higher packaging densities. Here two routes to the preparation of such nanoporous thin films are presented. A method has been de…
The novel organometallic−inorganic diblock copolymer, poly(ferrocenyldimethylsilane)- b -poly(dimethylsiloxane) (PFS- b -PDMS) (block ratio = 1.0:6.0) ( M n = 35 100 g/mol with a narrow molecular weight distribution M w / M n = 1.10 based upon gel permeation chromatography in THF using polystyrene standards) forms lon…
An improved cathode material for a solid‐oxide fuel cell would be a mixed electronic and oxide‐ion conductor with a good catalytic activity for oxygen reduction at an operating temperature T op ≥ 700°C and a thermal expansion matched to that of the electrolyte and interconnect. We report on the properties of Sr‐ and N…
Crystallization of mesoscale particles by a simple and general methodology is reported here. The versatility of this method is demonstrated by the production of monolayers, bilayers, and multilayers of polystyrene beads (see the scanning electron micrograph shown in the Figure). The method is useful, for example, for…
Ferromagnetic metal-based materials display interesting properties for microwave applications. Here the authors report obtaining ferromagnetic monodisperse particles in the nanometer size range by the polyol process. By accurate control of the particle size the influence of the particle upon the microwave permeability…
We study the dynamics of a ferromagnetic domain wall driven by an external magnetic field through a disordered medium. The avalanchelike motion of the domain walls between pinned configurations produces a noise known as the Barkhausen effect. We discuss experimental results on soft ferromagnetic materials, with refere…
Highly supercooled liquids with soft-core potentials are studied via molecular-dynamics simulations in two and three dimensions in quiescent and sheared conditions. We may define bonds between neighboring particle pairs unambiguously owing to the sharpness of the first peak of the pair correlation functions. Upon stru…
We develop a technique for simulation of the mechanics of micron-scale solid systems: coarse-grained molecular dynamics (CGMD). It captures the important atomistic effects without the computational cost of conventional molecular dynamics (MD). The CGMD equations of motion are derived directly from finite temperature M…
ZnS nanoparticles were prepared by chemical precipitation of Zn2+ with sulfur ions in aqueous solution. The ultraviolet-excited samples reveal detailed structure in the luminescence spectra. A doublet pattern observed in the long wavelength region is attributed to the coexistence of the two crystalline forms in ZnS pa…