Materials Literature
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Abstract N‐substituted maleimides have been investigated as thermal stabilizers for rigid polyvinylchloride (PVC) at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration of the polymer. The results reveal the higher stabilizing efficiency of these products relative to basic lead ca…
Electrochromic thin films of polyaniline were prepared by electropolymerization of aniline from an acidic aqueous solution on platinum and conducting glass surfaces. An in situ FTIR spectroelectrochemical technique was used to investigate structural changes of the film during oxidation and reduction. Coloring (oxidati…
The effect of YO 1.5 dopant on unit‐cell parameters of ZrO 2 (YO 1.5 =0 to 14.6 mol%) were examined by the X‐ray whole‐powder‐pattern decom‐position technique. The unit cell of monoclinic ZrO 2 has the largest expansion along the direction perpen‐dicular to (100). The rate of increase of the unit‐cell volume of monocl…
A previously reported lattice-dynamical model of β -cristobalite [Hua, Welberry, Withers & Thompson (1988). J. Appl. Cryst. 21 , 458–465], which assumed the Wyckoff C 9 structure but gave a satisfactory qualitative description of observed diffuse intensity in electron diffraction patterns, is shown to give atomic…
In situ measurements of electrostrictive strain and effective dielectric constant for two ferroelectric relaxor materials, lead magnesium niobate–lead titanate (0.9PMN · 0.1PT) and lead lanthanum zirconate titanate (PLZT 9.5/65/35), were performed in the temperature ranges near their respective mean Curie points under…
Coherent sidebranching of deep cells has been observed experimentally in the vicinity of the cell to dendrite transition. We propose that this phenomenon results from an oscillatory instability of deep cells, where cell widths and tip positions oscillate coherently in phase. We perform a linear-stability analysis of a…
Compositions to yield solid solutions were prepared by coprecipitation and firing. Fine active clusters of nickel were obtained by reduction. Phase changes were followed by thermal analysis, X‐rays, electron microscopy, surface area measurements, and reforming methane with CO 2 . Nickel on periclase remained active ov…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfluence of pressure on crystallization in poly(ethylene terephthalate)P. J. Phillips and H. T. TsengCite this: Macromolecules 1989, 22, 4, 1649–1655Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989https://pub…
We consider a semi-flexible chain adsorbed on a wall by a constant external field, h , or a short-range surface potential, V s . When the amplitude of h or V is decreased the system undergoes an unbinding transition; the properties of such transitions are studied here through various analytical and numerical methods (…
Using a new experimental technique, we have measured the fourth moment of the current distribution in two-dimensional random resistor networks. The fourth moment is proportional to relative resistance fluctuations in a network of noisy resistors, and, until now, noise measurements provided the only experimental probe…
Abstract Synchrotron x‐radiation has been used to follow the development of low‐angle diffraction in sharp fractions of polyethylene. The polymer is shown to crystallize in very thin lamellae which rapidly thicken in a single step to twice, three times, or four times the original thickness. This dramatic refolding is…
An in situ study of prismatic glide in beryllium is made to provide a simple model for understanding the anomalous increase in elastic limit as a function of temperature. This effect is also observed in several ordered alloys such as superalloys. In this paper, Part I, the mechanism controlling the deformation is stud…
A glucose dehydrogenase gene was isolated from Bacillus megaterium IWG3, and its nucleotide sequence was identified. The amino acid sequence of the enzyme deduced from the nucleotide sequence is very similar to the protein sequence of the enzyme from B. megaterium M1286 reported by Jany et al. (Jany, K.-D., Ulmer, W.,…
Abstract The surface of low density polyethylene has been grafted with glycidyl acrylate and glycidyl methacrylate by photoinitiation. ESCA measurements on the grafted surface showed a 72% coverage for glycidyl acrylate and 52% for glycidyl methacrylate after 10 min of grafting with UV irradiation. ATR–IR showed a 10…
The effect of annealing on the wetting behavior of Bi‐rich intergranular phases in ZnO:Bi:Co varistors was studied. The intergranular phase exhibits temperature‐dependent grain‐boundary wetting, with an average equilibrium dihedral angle of 0° at 1140°C and over 55° at 610°C. The temperature‐dependent wetting may be r…
Abstract Organic conjugated polymers and oligomers constitute a three‐dimensional network of molecular wires, in which all monomeric units can be functionalized with various prosthetic groups. By varying the nature of these groups, specific interactions with external physical or chemical phenomena can be developed in…
The relaxation kinetics and size of the third-order nonlinear susceptibility χ(3) of a homologous series of polycondensed thiophene-based polymers and polysilane polymers were determined by ultrafast nonlinear laser techniques. The wavelength dependence over 530–1060 nm of χ(3) was measured for polycondensed thiophene…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymeric monolayer dynamics at the air/water interface by surface light scatteringMasami Kawaguchi, Bryan B. Sauer, and Hyuk YuCite this: Macromolecules 1989, 22, 4, 1735–1743Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published iniss…
Two types of diamagnetic luminescence centers were found in VAD SiO 2 glass sintered under reducing atmospheres. One of the PL centers, which had an excitation band at 5.17 eV (240 nm) and two emission bands, at 4.2 eV (295 nm) and 3.1 eV (400 nm), was mainly detected in the glasses sintered under H 2 /He atmosphere.…
Abstract Acrylic monomers were graft copolymerized onto gelatin chains using potassium persulfate in aqueous medium. The graft copolymers were then treated with glutaraldehyde to establish crosslinks between gelatin macromolecules. This yielded a rigid water insoluble protein network sporting grafted chains at random.…