Materials Literature
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Tensile tests with loading and unloading under various strain rates ε^^· were performed for TiNi shape memory alloy wires at various constant temperatures. The influence of strain rate on the stress-strain-temperature relationship was investigated. The main results are summarized as follows. ( 1 ) For ε^^· < 10%/min,…
Experimental Barkhausen data are presented for XC10 French steel at various stress levels. The experimental data show an apparent almost linear correlation with stress of WH (hysteresis loss) and WBN (Barkhausen noise amplitude integrated over H). A model previously suggested by Sablik for Barkhausen noise stress and…
1,3-Diaminoadamantane (I) was used as a monomer with various aromatic dicarboxylic acyl chlorides and dianhydrides to synthesize polyamides and polyimides, respectively. Polyamides having inherent viscosities of 0.10–0.27 dL/g were prepared by low-temperature solution polycondensation. The polyamides were soluble in a…
Measurements of effective magnetic anisotropy energy of epitaxial Cu/Ni/Cu(001) sandwiches are analyzed as a function of Ni film thickness $h$. The magnetization easy axis is perpendicular to the films for $20<h<140$ \AA{}. The magnetic anisotropy is best described by inclusion in the effective anisotropy energy…
Crystallization is induced in amorphous 80 nm films of Ge48Te52 by electron irradiation to produce structures with characteristic dimensions as small as of 10–100 nm. The experiments are performed in a 200 keV field-emission scanning transmission electron microscope (TEM/STEM) that provides an electron probe about 1–2…
A general theory is developed for determining the most efficient magnetic structure that generates a specified magnetic field. The structure is assumed to be composed of linear, isotropic magnetized material, occupying a given geometrical region. The efficiency is quantified by a figure of merit defined as the externa…
A model system of linear ethylene glycol terminated poly(ethylene terephthalate) oligomers of the general formula H–[GT]n–G (where G is an ethylene glycol unit and T represents a terephthalic acid unit) was synthesized and exposed to an oxygen plasma. The degradation of the oligomers was investigated by matrix-assiste…
The number of isolated Mn2+ ions and Mn2+ clusters in ZnS:Mn powder and thin films has been studied using Mn2+ spectra measured at room temperature with an X-band electron-paramagnetic-resonance spectrometer. While the concentration of the isolated Mn2+ ions decreases with increasing Mn concentration, the concentratio…
Recently carbon nanotubes with coiled structures (carbon helix) were found and have attracted much attention. The electronic structures of two families of such helices, whose structures are proposed by two of the present authors (Ihara and Itoh), are calculated using a tight-binding method based on development maps. I…
The Holstein-Hubbard model is used to study high-temperature (T\ensuremath{\gtrsim}${\mathit{T}}_{\mathrm{phonon}}$/3) hopping transport when it is energetically favorable for carriers to pair as singlet small bipolarons. The semiclassical rates for one-electron transfers involving small polarons are found to be much…
A short group-theoretical discussion is given of phonon symmetries in different phases of the Pb(ZrxTi1−x)O3 (PZT) perovskite together with a description of the degeneracy splitting in consequence of the long-range Coulomb fields both in the paraelectric cubic phase and ferroelectric tetragonal and trigonal phases. Ph…
We have measured Raman spectra of free-standing porous silicon at 10 K. Porous silicon samples were prepared in aqueous and ethanoic electrolytes and the scattering was measured in the range of one- through four-phonon processes. A quantum size effect is clearly observed in the spectral change of the first- and second…
A magnetic field induced insulator to metal transition has been observed in both polycrystalline and single crystals samples of Pr0.7Ca0.3MnO3. Application of a magnetic field leads to a first-order phase transition from an insulating to a conducting state at low temperatures. The hysteresis associated with this trans…
A photodiode has been constructed from lightly boron doped, Si supported, thin film chemically vapor deposited (CVD) diamond which shows over five orders of magnitude discrimination between deep UV (≤220 nm) and visible light. A thin (10 nm) gold Schottky barrier with an associated Ti–Ag–Au ohmic contact was used to c…
For more then one century it has been observed that stress corrosion cracking (SCC) and corrosion fatigue (CF) corresponds to synergetic effects between corrosion and mechanics. Researchers and engineers have tried to translate such effects through empirical damage laws, in particular to predict crack velocities in me…
Hydrodynamic slip due to lack of molecular interfacial interactions is demonstrated rheologically as a function of molecular weight and temperature, by comparing poly(dimethyl siloxane) (PDMS) suspensions of bare and silane-treated glass spheres. The magnitude of interfacial slip between treated spheres and PDMS matri…
Analysis of x-ray diffraction from a single crystal of bis-benzene-1,2-dithiolato-Au(IV) [Au${(\mathrm{bdt})}_{2}$] at 125 K reveals a superstructure along the stacks of Au${(\mathrm{bdt})}_{2}$ molecules corresponding to a dimerization of the molecules along the stack. Within a dimer, intermolecular sulfur-sulfur con…
The demand for biodegradable chemicals is increasing as chemical producers and consumers anticipate more stringent standards for degradability in new and existing products. Poly(aspartic acid) (PAA) is an example of a chemical that shows promise as a biodegradable replacement for polyacrylic acid, a nonbiodegradable p…
Transcrystallization of polypropylene (PP) on the polytetrafluoroethylene (PTFE) fiber was investigated. Both nucleation rate and crystal growth rate were determined by a polarized optical microscope. Based on the theory of heterogeneous nucleation, it has been found that the induction time can correlate well with the…
Zirconia–alumina transformation-toughening nanolaminates were fabricated by reactive sputter deposition. The average crystallite size and volume fraction of each zirconia polymorph were determined by x-ray diffraction. The volume fraction of tetragonal zirconia, the phase necessary for transformation toughening, was f…