Materials Literature
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The biosynthesis of methionine in Escherichia coli is under complex regulation. The repression of the biosynthetic pathway by methionine is mediated by a repressor protein (MetJ protein) and S-adenosyl-methionine which functions as a corepressor for the MetJ protein. Recently, a new regulatory locus, metR, has been id…
An experimental review on electric field effects in blue phases is presented. Electric fields have a profound effect on these phases which appear in chiral liquid crystals. In addition to producing elec-trostrictive effects on blue phase lattices, they also cause new field induced phases—tetragonal BPX, hexagonal BPH3…
Molecular-dynamics simulations of 500 particles have been performed to study the icosahedral order and the defects in the supercooled liquid and glass states of metallic ${\mathrm{Mg}}_{3}$${\mathrm{Ca}}_{7}$. Not only are Frank-Kasper polyhedra and Bernal ``hole'' polyhedra detected, but also a variety of defective i…
Thin polycrystalline films of VO2 and V2O3 were deposited on a variety of substrates using a sol-gel process. The orientation, microstructure, optical constants, and optical and electrical switching behavior are presented. These films exhibited sharp optical switching behavior even on an amorphous substrate such as fu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh internal phase water-in-oil emulsions: influence of surfactants and cosurfactants on emulsion stability and foam qualityJoel M. WilliamsCite this: Langmuir 1991, 7, 7, 1370–1377Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published…
Radiometrically calibrated spectroscopic techniques employing an integrating-sphere detection system have been used to determine the fluorescence quantum efficiencies for two commercially available Nd3+-doped phosphate laser glasses, LG-750 and LG-760. Quantum efficiencies and fluorescence lifetimes were measured for…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTXPS study of self-doped conducting polyaniline and parent systemsJ. Yue and A. J. EpsteinCite this: Macromolecules 1991, 24, 15, 4441–4445Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published inissue 1 July 1991https://pubs.acs.org/doi/…
The complete series of the recommended generic biological tests for materials and devices in contact with tissues and tissue fluids and blood have been carried out by an independent testing laboratory on the elastic protein-based (bioelastic) polymer, Poly(L-Val 1 -L-Pro 2 -Gly 3 -L-Val 4 -Gly 5 ) with a degree of pol…
Several oxides of vanadium undergo a transition from a semiconductor or insulating state to a metal phase at a critical temperature. Vanadium dioxide undergoes this transition near 68 degrees C, while V(2)O(5) undergoes a similar phase transition near 257 degrees C. During the transition a change in oxide crystal stru…
In order to examine the potential correlation between infrared absorption spectra and 3(10)- and alpha-helices and beta-bend ribbon structures, the secondary structures of synthetic peptides known to contain pure 3(10)-helices, mixed 3(10)/alpha-helices, and pure beta-bend ribbon structures, based upon X-ray diffracti…
A three-dimensional Landau-Ginzburg model has been constructed to describe the tetragonal twin structures resulting from a first-order ${\mathit{O}}_{\mathit{h}\mathrm{\ensuremath{-}}}$${\mathit{C}}_{4\mathit{v}}$ proper ferroelectric phase transition in perovskites. The model takes into account the nonlinear and nonl…
Abstract This review examines some recent developments in the field of reactive compatibilization of polymer blends by melt processing in extruders and intensive batch mixers. Three routes to reactive compatibilization are considered, namely, the use of suitably functionalized blend constituents, the incorporation of…
A new class of materials is proposed to improve the electrocatalytic activity of hydride forming intermetallic compounds of the AB 5 ‐type without making use of highly electrocatalytic precious metals like Pd or Pt. These materials, denoted as AB 5.5 , consist of two different crystallographic phases: the bulk phase,…
By combining Auger data on the width of an oxygen depletion layer near the Pt electrodes with a modified Langmuir–Child law for the leakage current: I(V) = aV + bV2, we deduce parameters related to the space-charge density and field in 210-nm-thick PbZr1−xTixO3 memories. The results are compared with the space charge…
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It is suggested that in many ferromagnetic materials there may occur particles distinct in magnetic character from the general matrix, and below the critical size, depending on shape, for which domain boundary formation is energetically possible. For such single-domain particles, change of magnetization can take place…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical x-ray absorption fine structure standardsJ. J. Rehr, J. Mustre de Leon, S. I. Zabinsky, and R. C. AlbersCite this: J. Am. Chem. Soc. 1991, 113, 14, 5135–5140Publication Date (Print):July 1, 1991Publication History Published online1 May 2002Published inissue 1 Jul…
It is proposed that permanent magnets can be made of composite materials consisting of two suitably dispersed ferromagnetic and mutually exchange-coupled phases, one of which is hard magnetic in order to provide a high coercive field, while the other may be soft magnetic, just providing a high saturation J/sub s/, and…
Bond-length and bond-angle parameters are derived from a statistical survey of X-ray structures of small compounds from the Cambridge Structural Database. The side chains of the common amino acids and the polypeptide backbone were represented by appropriate chemical fragments taken from the Database. Average bond leng…