Materials Literature
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This work reports the synthesis and characterization of diamantane-based polyimides obtained from 1,6-bis[4-(4-aminophenoxy)phenyl]diamantane and various aromatic tetracarboxylic dianhydrides. This novel polyimide exhibits a low dielectric constant (2.56−2.78), low moisture absorption (<0.292%), good solubility, and h…
Enzymatic ring-opening polymerization of medium-size lactones, ϵ-caprolactone (ϵ-CL) and δ-valerolactone (δ-VL), was performed by using a lipase as a catalyst. For the polymerization of ϵ-CL in bulk, a lipase derived from Pseudomonas fluorescens (lipase PF) showed the highest catalytic activity among the powdery lipas…
▪ Abstract This article reviews the defect chemistry of perovskite ferroelectric oxides such as barium titanate and lead zirconate titanate. Such metal oxides are being considered for a wide range of applications that include nonvolatile memories and dynamic random access memories. Time-dependent degradation of these…
Transient cavitation and shockwave generation produced by pulsed-dye and holmium:YAG laser lithotripters were studied using high-speed photography and acoustic emission measurements. In addition, stone phantoms were used to compare the fragmentation efficiency of various laser and electrohydraulic lithotripters. The p…
Biomaterial-mediated complement activation repeatedly has been invoked as a trigger of phagocyte reactions and inflammation. However, a direct correlation between complement activation and inflammatory responses to biomaterial surfaces has yet to be established. Using an animal implantation model and gold surfaces bea…
To better understand the mechanism of collagen fibrillogenesis, we studied how various sugars and polyols affect the formation and stability of collagen fibers. We combined traditional fiber assembly assays with direct measurement of the interaction between collagen triple helices in fibers by osmotic stress and X-ray…
The hydration of MgAl layered double hydroxides (LDHs) with interlayer terephthalate anions and controlled layer charge is studied. A combination of powder X-ray diffraction (PXRD), thermal gravimmetry (TG), and computer simulation is used to study in detail the effect of layer charge density and interlayer water cont…
One can increase the angular tolerance of resonant grating filters without modifying the spectral bandwidth by adding a second grating component parallel to the first one. The angular tolerance and the filter linewidth can be controlled by the designer in an independent way. Numerical results show that this property p…
The occurrence of hausmannite with an apparent Curie temperature close to 750 K, instead of 41.8 K was recently described from hydrothermally altered manganese ore from the Kalahari manganese field, South Africa. The unusual magnetic properties were related to the substitution of Fe 3+ for Mn in the hausmannite struct…
Ferrimagnetic behavior has been found for the one-dimensional azido-bridged compound [Cu(3-Clpy)2(N3)2]n, in which 3-Clpy is 3-chloropyridine. According to the structural data, this unusual magnetic interaction for an SA = SB system is explained in terms of the topology of the chain: alternating two ferromagnetic with…
Random defects destroy long-range phase coherence, and inhibit the metal-insulator transition in the charge density wave (CDW) system $1T\ensuremath{-}{\mathrm{TaS}}_{2}$. Photoelectron spectroscopy with high resolution reveals corresponding changes in the electronic structure. Core level spectra indicate a temperatur…
Colonization dynamics and metabolism of algal communities on wood (small pieces of Douglas fir) and artificial rock (tiles) substrata were investigated in an open reach in Mack Creek, Cascade Mountain Range, Oregon, for 42 days. Chlorophyll a concentration was not significantly different between the two algal communit…
▪ Abstract Polymer phases can be described in the same way as phases in other condensed matter using a number density operator and its correlation functions. This description requires the understanding of symmetry operations and order at different atomic and molecular levels. Statistical mechanics provides a link betw…
The drainage of liquid foams involves the interplay of gravity, surface tension, and viscous forces. Three experimentally accessible configurations are modeled analytically using a one-dimensional nonlinear partial differential equation called the foam drainage equation: free drainage where liquid drains from an initi…
The deposition of copper by means of atomic layer epitaxy is reported. Using Cu(II)‐2,2,6,6‐tetramethyl‐3,5‐heptanedionate as the precursor, pure and specular copper films were deposited at deposition temperatures below 200°C. This is more than 150°C lower than in previous reports for the same precursor where chemical…
The stability of diamond under pressure and the structure of hypothetical high-pressure phases have been a controversial issue for a long time. “Will diamond transform under megabar pressures?” asked Yin and Cohen in the title of their paper [Phys. Rev. Lett. 50, 2006 (1983)] which attempted to predict an answer to th…
An atomistic direct diagonalization pseudopotential approach has been used to analyze the optical excitation spectra of CdSe quantum dots for up to 1.5 eV about the band gap. Good agreement is obtained with experiment for all the eight excitonic transitions, without resorting to fitting to the experimental data on dot…
The dielectric behavior of alkylcyanobiphenyls (5CB and 8CB) confined in porous matrices with randomly oriented, interconnected pores with two different mean pore sizes (1000 and 100 \AA{}) has been investigated by means of broadband dielectric spectroscopy in the frequency range from 1 mHz to 1.5 GHz. The confinement…
Magnetization and electrical resistivity studies have established that ${\mathrm{La}}_{0.5}{\mathrm{Ba}}_{0.5}{\mathrm{CoO}}_{3\ensuremath{-}\ensuremath{\gamma}}$ (LaBaC) is a metallic ferromagnet whereas ${\mathrm{Pr}}_{0.5}{\mathrm{Ba}}_{0.5}{\mathrm{CoO}}_{3\ensuremath{-}\ensuremath{\gamma}}$ (PrBaC) is a magnetic…
Wide band dielectric and electro-optic spectroscopy of an antiferroelectric liquid crystal (AFLC) has been carried out over a range of frequencies from 1 kHz to 1 GHz. The AFLC sample under investigation possesses a variety of different ferri-, ferro-, and antiferro-electric phases. Dielectric spectroscopy of the LC c…