Materials Literature
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Discomfort results when sweat accumulates on the skin. The sorption of water vapor by hygroscopic clothing near the skin and its release when the clothing moves away from the body can enhance sweat removal. Such a process depends on the relative humidity being higher near the skin than in the ambient atmosphere, and m…
Gypsum and halite are the most common salts in reg soils developed on alluvial parent material under extremely arid conditions in the Negev Desert, Israel. The aim of this paper is to document the changes in the micromorphology of these salts at different stages of Reg soil development on two alluvial fan chronosequen…
Tension‐tension cyclic‐fatigue tests of a two‐dimensional‐woven‐SiC‐fiber‐SiC‐matrix composite (SiC/SiC) prepared by chemical vapor infiltration (CVI) were conducted in air at room temperature and in argon at 1000°C. The cyclic‐fatigue limit (10 7 cycles) at room temperature was ∼160 MPa, which was ∼80% of the monoton…
X-ray structure determination and pyroelectric and piezoelectric measurements have been carried out on mesogenic mixtures composed of achiral side chain polymers and their monomers. Certain mixtures show antiferroelectric polarization hysteresis loops in the mesophase which was shown to be a bilayered smectic C, while…
The Field Induced Spin Density Waves (FISDWs) found in organic conductors represent a unique series of transitions which meld the one-dimensional physics of the Peierls instability with the two-dimensional physics of the Quantum Hall Effect. This paper presents a pedagogical introduction to the FISDW's in the Bechgaar…
The dielectric properties of nematic liquid crystal (4-cyano-4′-n-pentylbiphenyl: 5CB) cells in the ultralow frequency regime was investigated. A dielectric relaxation, whose relaxation time is 160 s, is observed at 303 K, and the dielectric relaxation is found to be independent of applied electric field. It is shown…
It is confirmed that the calculation of the demagnetizing field in micromagnetic simulations can be accelerated significantly by using the discrete convolution theorem and the fast Fourier transform (FFT). When the magnetization distribution is periodic, application of the theorem to the demagnetizing field calculatio…
X-ray photoemission measurements of the core levels and valence electronic structure of LaCo${\mathrm{O}}_{3}$ and ${\mathrm{La}}_{0.5}$${\mathrm{Ca}}_{0.5}$Co${\mathrm{O}}_{3}$ high quality epitaxial films are presented. Shifts of the core levels and main valence band features are consistent with a doping-induced cha…
The morphologies of thin, substrate-free block copolymer films have been examined by cross-sectional TEM. Two poly(styrene-b-butadiene) diblock copolymers were studied: one that forms PS cylinders and the other that forms PB cylinders in the bulk. Films were annealed while supported by metal TEM grids, embedded, and u…
Abstract A new class of amphiphilic macromolecules has successfully been synthesized by creating well‐defined diblock copolymers of polystyrene (PS, M n 3.2 × 10 3 , M w / M n =1.04) with poly‐(propylene imine) dendrimers. A poly‐styrene core molecule with a primary amine end‐group was prepared by a quantitative thre…
The results of Rietveld refinements using synchrotron X-ray powder diffraction data collected in transmission mode with a new flat imaging-plate (IP) technique agree with those obtained from other techniques, m-ZrO2 was chosen as test compound because it was the standard selected by the Commission on Powder Diffractio…
A series of novel, unsymmetrically substituted metallo-phthalocyanines was synthesized, along with their symmetrically substituted analogs, and the effects of structure and metal substitution on their photophysical and photoredox properties were investigated. The macrocycles were synthesized using a mixed-condensation…
The electrical resistivity of polymer composites is studied as a function of temperature. The initial resistivity ρ of thermoplastic or thermoset containing a metallic filler is in the range of 1–10×10−2 Ω cm. Around the curing temperature of epoxies, the resistivity increases by eight to twelve orders of magnitude. F…
The mechanical behavior of reaction‐sintered alumina: 30 vol% calcium hexaluminate (Al 2 O 3 :CaAl 12 O 19, or A1 2 O 3 : CA 6 ) composites was evaluated using the indentation strength in bending technique. A composite in which the hexaluminate (CA 6 ) phase possessed a platelike morphology showed more‐pronounced R ‐c…
A gene located at 443 kilobases on the Escherichia coli chromosome (subsequently designated ribE) was expressed in a recombinant E. coli strain and was shown to code for the enzyme 6, 7-dimethyl-8-ribityllumazine synthase. The recombinant enzyme was purified to homogeneity. The protein is an icosahedral capsid of 60 s…
The kinetics and mechanism of transpassive dissolution of thin, sputter‐deposited Cr 2 O 3 films and passivated Cr were studied with in situ x‐ray near‐edge spectroscopy in 1 M H 2 SO 4 , borate buffer (pH 8.4), and 1 M NaOH. The onset potentials of the transpassive dissolution and the plateau potentials during galvan…
An isotropic high‐density graphite was used as a polarizable electrode of all‐solid state electric double‐layer capacitor using polyethylene oxide (PEO) or gel PEO electrolyte. The all‐solid‐state capacitor with high‐density graphite electrodes possesses higher differential capacity than the other flat electrodes in s…
Phonon modes of CdSe quantum dots in various glass matrices are investigated by Raman spectroscopy. The phonon energies are observed to be dependent on the host matrix as well as the quantum dot size. We have shown that the lattice contraction effect must be introduced to explain the observed differences of the phonon…
The microscale syntheses of Tetraphenylporphyrin, H 2 (TPP), and the corresponding metalloporphyrins Zn II (TPP) and Ni II (TPP) are reported. H 2 (TPP) is synthesized by the condensation of benzaldehyde and pyrrole, and the subsequent metallation of H 2 (TPP) is achieved with anhydrous Zn II Cl 2 or Ni II Cl 2 in DMF…
Using a pin‐on‐plate tribometer with the reciprocating motion of SiC against yttria‐doped tetragonal zirconia polycrystal (Y‐TZP) plates, the friction and wear of Y‐TZP ceramics were investigated as a function of grain size in dry N 2 at room temperature. The results showed that the overall wear resistance increased a…