Materials Literature
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Phase boundary and domain structure in relaxor ferroelectrics Pb(Zn 1/3 Nb 2/3 )O 3 /9%PbTiO 3 were observed using a (111) plate under a polarization microscope. The dielectric constant was measured simultaneously to determine exact transition temperatures and to connect the dielectric behavior with phase boundary mov…
Chiral polyaniline colloids have been generated via the electrohydrodynamic polymerization of aniline in aqueous (+)- or (−)-10-camphorsulfonic acid (HCSA) using polystyrene sulfonate (PSS) as a steric stabilizer and codopant. Potentiostatic polymerization at +0.9 V (vs Ag/AgCl) was employed. The colloidal PAn·HCSA/PS…
Bismuth sodium titanate, (Bi 1/2 Na 1/2 )TiO 3 (BNT)-based solid solution, a (Bi 1/2 Na 1/2 )TiO 3 – b KNbO 3 – c 1/2(Bi 2 O 3 ·Sc 2 O 3 ) ( a + b + c =1), [KTNS(100 a /100 b /100 c )], was studied for its dielectric, ferroelectric and piezoelectric properties, as a new group of lead-free piezoelectric ceramics. Elect…
We report neutron scattering experiments on several Al-Pd-Mn liquid alloys with Mn content between 3.5 and 7.2 at. % which are in thermodynamical equilibrium with icosahedral quasicrystalline or approximant phases. The results reveal an overall similarity between the structure factor in the solid and in the liquid sta…
We investigate the local structural heterogeneities that may appear in liquid water by studying a model of interacting water pentamers. We find local energy minima which we identify with well-defined configurations, and advance the hypothesis that one of these configurations may be related to local “high-density” stru…
The photoabsorption and photoluminescence properties of two-coordinated Si, Ge, and Sn defect centers and the magnetic interactions of the corresponding $[=\mathrm{S}\mathrm{i}\ensuremath{-}\mathrm{H}{]}^{\ifmmode\bullet\else\textbullet\fi{}},$ $[=\mathrm{G}\mathrm{e}\ensuremath{-}\mathrm{H}{]}^{\ifmmode\bullet\else\t…
In this work the lyotropic liquid crystal nematic state of poly( n -hexyl isocyanate) (PHIC) was converted to the cholesteric state by doping with a variety of chiral small molecules and with optically active polyisocyanates. Circular dichroism experiments in dilute isotropic PHIC solutions show that several of the sm…
Phase transition in [N(C2H5)4]2ZnCl4 has been investigated by means of X-ray diffraction and high-resolution 13C-NMR. Structure determination shows that [N(C2H5)4]+ ion involves disordering between two Nordic crosses at room temperature. 13C-NMR spectra considerably broaden near the transition point in the high temper…
In order to develop a corrosion-free halogen gas delivery system for use in semiconductor manufacturing, Cr2O3 passivation of ferritic and austenitic stainless steels has been investigated. It has been shown that a Cr2O3 layer can be formed on an electropolished (EP) surface of ferritic 26Cr–1Mo stainless steel by oxi…
Abstract Using an adiabatic calorimeter direct measurements of the heat capacity of the liquid Si 15 Te 85 , Ge 15 Te 85 , Sn 15 Te 85 , Pb 11 Te 89 , Pb 11 Te 89 and Bi 10 Te 90 alloys and of liquid tellurium have been performed. The heat capacity has been measured as a function of temperature up to about 100 K above…
Using a previously developed theory of nematic liquid crystals (Singh, Y., and Singh, K., 1986, Phys. Rev. A, 33, 3481) we present the calculation of elastic constants of discoticnematic liquid crystals and study the variation of elastic constants with packing fraction. The expressions for elastic moduli associated wi…
Abstract Lichtquellen hoher Leuchtdichte sind Schlüsselkomponenten für das Projektionsfernsehen. Mit der Entwicklung der UHP‐Lampe (Ultra‐High‐Performance) von Philips wurde hier ein entscheidender Durchbruch erzielt. Durch die erstmalige Realisierung einer Quecksilber‐Höchstdruckentladung mit einem Halogen‐Kreisproze…
Carbon nanostructures were prepared by catalytic decomposition of benzene on Co/SiO2 catalysts at 873 K. As a function of particle size and reactive mixture, carbon filaments and nanotubes were obtained and various shapes observed such as straight, curved and helically-coiled nanotubes. Particularly, it was shown that…
A two‐dimensional model is developed for transport of oxygen in a porous solid oxide fuel cell (SOFC) cathode with negligible oxygen ion conductivity in the bulk. Adsorption and surface diffusion of oxygen adsorbates on the pore walls interfacial diffusion of adsorbates, and electrochemical reaction kinetics at the el…
Oxide film characterizations and electrochemical measurements were carried out on crevices of austenitic stainless alloys to investigate the acceleration mechanism of intergranular stress corrosion cracking (IGSCC) in high-temperature water. When the chromium concentration was sufficient, type 304 (UNS S30400) stainle…
Abstract In order to evaluate the compatibilizing effects of isocyanate (NCO) functional groups on ethylene vinyl alcohol copolymer/high density polyethylene (EVOH/HDPE) blends, HDPE grafted with 2‐hydroxyethyl methacrylate‐isophorone diisocyanate (HDEP‐g‐HI) was prepared and blended with EVOH. The grafting was confir…
Using mean field theory with a P2θ2 coupling term in the free energy expansion, we calculate the polarization as a function of temperature for the smectic A-smectic C* phase transition in a liquid crystalline material. Our calculated polarization values are in good agreement with the experimental data.
The role of the substrate in determining heat dissipation in high power electronics is calculated, subject to convective cooling in the small Biot number regime. Analytical models that exploit the large aspect ratio of the substrate to justify approximations are shown to predict the behavior with good accuracy over a…
Radiation damage of polymethylmetacrylate (PMMA) is investigated irradiating thin films with 100–300 keV helium beams. The damage is deduced by measuring in situ the molecular ejection from the irradiated polymer with a quadrupole mass spectrometer. The main ejected molecular masses are 2, 15, 16, 18, 26, 28 and 44, c…
Poly(methyl methacrylate) microspheres [poly(SerMA-co-MMA), poly(AlaMAm-co-MMA), poly(AlaEMA-co-MMA), and poly(AlaMAm/AlaEMA-co-MMA)] modified with O-methacryloyl-L-serine (SerMA), N-methacryloyl-L-alanine (AlaMAm) and L-alanine 2-methacryloyloxyethyl ester (AlaEMA) were prepared by the emulsifier-free emulsion copoly…