Materials Literature
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It has been known that blends of poly(ε-caprolactone) (PCL) and poly(styrene- co -acrylonitrile) (SAN) show a miscibility window in a relatively narrow range of copolymer composition in SAN. In order to study the interactions in this miscibility window in detail, FTIR and calorimetric measurements were carried out by…
Barium hexaferrites of compositions BaO·(6- x )Fe 2 O 3 · x Bi 2 O 3 with 0 \leqslant x \leqslant0.4 have been synthesized by the ceramic calcination route. The bismuth substituted hexaferrites exhibit dc electrical conductivities more than two orders of magnitude higher than the pure ones. This is believed to arise d…
The amino acid leucine has been shown previously to be transported into a yeast cell by at least three permeases: the general amino acid permease, a high-affinity permease (S1) and a low-affinity permease (S2). We isolated the gene BAP2 as a multicopy suppressor of the YPD- phenotype of aat1leu2 yeast. BAP2 has been i…
In-situ measurements of the motion of special and non-special 〈111〉 tilt grain boundaries in aluminium bicrystals of different purity show that even in very pure aluminium the activation parameters of the grain boundary mobility depend on the content of soluble impurities. The investigations are described in the frame…
We prove a conjecture of A. Hof, O. Knill and B. Simon [Commun. Math. Phys. 174, 149–159 (1995)] by showing that the Rudin-Shapiro sequence is not palindromic, i.e., does not contain arbitrarily long palindromes. We prove actually this property for all paperfolding sequences and all Rudin-Shapiro sequences deduced fro…
Becker and Mott have provided different formulae for the thermal activation energy of a process that occurs under stress. As the applied stress tends towards the critical stress, Becker's formula requires the smaller activation energy. We argue that, while the Mott formula represents the energy required for the system…
The first polarized low-temperature absorption and luminescence spectra of manganese-doped crystals of BaSO(4) containing essentially MnO(4)(2)(-) are reported. By using a flux composed of NaCl, KCl, and CsCl we were able to grow BaSO(4):Mn(6+) crystals below 620 degrees C. This prevents the simultaneous presence of M…
The values for Young's modulus of porous single-crystal Ni in the [100] and [111] directions are computed using the embedded-atom method (EAM). Both pore volume fraction and pore size (defined by ratio S/R of the flaw size to pore radius) are varied. A reduction in Young's modulus with increasing pore volume fraction…
Abstract A high molecular weight, linear aromatic poly(ether ketone ether ketone ketone) (PEKEKK) has been synthesized by electrophilic Friedel‐Crafts acylation condensation of 1,4‐diphenoxybenzophenone with terephthaloyl chloride. The syntheses were performed as precipitation polycondensations, and the polyketones we…
Director fluctuations in nematic liquid crystals are readily analyzed in terms of the normal modes of the director field. In this paper, we examine the dynamics of fluctuations in the radial director field of a spherical nematic droplet in terms of its normal modes. We find independent twist-bend and splay-bend modes…
A magnetic field sensor based on the dependence of the magnetostrictive delay line (MDL) response on its biasing magnetic field is presented in this paper. Such a sensor can be formed in an integrated array measuring the distribution of field along the MDL axis. Experimental results are reported for amorphous FeSiB wi…
A bisphthalonitrile monomer containing bismaleimide groups was synthesized using 4,4′-bismaleimidodiphenylmethane and 4-aminophenoxyphthalonitrile. The structure of the monomer was confirmed by elemental analysis and IR spectroscopy. With this monomer, a phthalocyanine resin containing bismaleimide groups was obtained…
Photocorrosion of n-GaAs and passivation by Na 2 S have been studied in a working photoelectrochemical cell as a function of crystal face orientation. Time-resolved photoluminescence studies of the (100), (110), and (111)B faces of n-GaAs show that Na 2 S provides a similar degree of corrosion protection to the (100)…
Various high-density DRAM and FRAM technologies currently under investigation utilize high-dielectric constant materials requiring noble metal or refractory metal oxide electrodes. In this paper we describe a study of platinum patterning by reactive ion etching (RIE). Platinum films were etched in a rf diode parallel…
Other| April 01, 1997 Natural kalsilite, KAlSiO2, and P31c symmetry; crystal structure and twinning Daniela Cellai; Daniela Cellai Dipartimento di Scienze della Terra, Florence, Italy Search for other works by this author on: GSW Google Scholar Paola Bonazzi; Paola Bonazzi Search for other works by this author on: GSW…
This paper describes the electrochemical characterization of electrode-confined siloxane polymers that contain both naphthoquinone (NQ) and benzylviologen (BV 2+ ) subunits. These “homopolymers,” abbreviated (NQ-BV 3+ ) n and (NQ-BV-BV 5+ ) n, are derived from monomers, 2-chloro-3-[[2-{dimethyl[[[[ N ‘-[[4-(trimethoxy…
Diaminopimelate (DAP) is used by bacteria for the synthesis of lysine. In many species of bacteria, including mycobacteria, DAP is also used for peptidoglycan biosynthesis. In this report we describe the cloning of the dapB gene encoding dihydrodipicolinate reductase (DHPR), which catalyzes a key branch point reaction…
A density functional investigation of methyltrioxo−rhenium and its lower homologue methyltrioxo−technetium studying the influence of relativistic effects on the reactivity of the two metal centers is presented. In order to quantify the Lewis acidity of the central metal atom, the adduct formation with NH 3 as a probe…
The effects of several oxoacid salts (sulfate, molybdate, phosphate, and nitrate) on pitting behavior of type 304 (UNS S30400) stainless steel (SS) were examined to characterize their performance in high-temperature chloride solutions through measurement of pitting temperatures (Tp) and potentials (Ep). Measurement of…
This paper presents a control law for shape memory alloy (SMA) wire actuators. Unlike most laws reported in the literature, this control law includes both a feedback and an open-loop part. The open-loop part takes into account the stress - strain - temperature behaviour of SMA wires, as well as the dynamics of the hea…