Materials Literature
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Six polyurethanes containing coumarin dimer components in the main chain have been prepared by polyaddition of diisocyanates with anti head-to-head 7-hydroxycoumarin dimer or anti head-to-tail 7-hydroxy-4-methylcoumarin dimer. 7-Acetoxycoumarin and 7-acetoxy-4-methylcoumarin were first prepared and then photodimerized…
Self-diffusion coefficients obtained by the NMR spin-echo method are reported for water at temperatures below 0 °C and at pressures up to 350 MPa in the liquid region bounded by the ice I and ice III phases. The data are compared with other measurements in this region.
We report a shear wave reflection technique which allows time- and temperature-dependent measurements of the complex dynamic shear modulus (G*=G′+iG′′) or the dynamic shear viscosity (ηs′) in the ultrasonic frequency range (3–40 MHz). The shear wave reflection method developed by Mason et al. [Phys. Rev. 75, 936 (1949…
The bacterial copolyester poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) was produced with Alcaligenes eutrophus DSM 545 from glucose and sodium propionate in a fed-batch fermentation with both nitrogen limitation and low dissolved-oxygen concentrations. When the dissolved-oxygen content was kept between 1 and 4% of ai…
A high-resolution calorimetric study has been made on the smectic-A to nematic phase transition in liquid crystals perturbed by the dispersion of 70-\AA{}-diam silica spheres (aerosils). The specific heat peak of this transition decreases in amplitude and shifts to lower temperatures with increasing silica density. Ho…
Photoexcited [Ru(bpy) 3 ] 2+ (bpy = 2,2‘-bipyridine) can be quenched with [Co(NH 3 ) 5 Cl] 2+ to give [Ru(bpy) 3 ] 3+; this photogenerated oxidant ( E 0 = 1.25 V vs NHE) reacts with horseradish peroxidase isoenzyme c (HRPc) to produce oxidized protein species. Spectra and kinetics measured by laser-flash transient spe…
The diffusion and gelation dynamics of nonsolvent-induced phase inversion in several polyethersulfone (PES)/solvent/nonsolvent systems are observed using a dark-ground optical technique. The observed dynamics are correlated with the resultant morphologies of the solidified gels obtained via scanning electron microscop…
Abstract The Fourier transform Raman spectra of the kaolinite minerals have been measured in the 50–3800 cm −1 region using near infrared spectroscopy. Kaolinites are characterized by remarkably intense bands in the 120–145 cm −1 region. These bands, attributed to the O-Si-O and O-Al-O symmetric bending modes, are bot…
The Bacillus subtilis L-arabinose metabolic genes araA, araB and araD, encoding L-arabinose isomerase, L-ribulokinase and L-ribulose-5-phosphate 4-epimerase, respectively, have been cloned previously and the products of araB and araD were shown to be functionally homologous to their Escherichia coli counterparts by co…
Whole and headless shrimp (Pandalus borealis) were dipped in various concentrations of chitosan solution and stored for 20 days at 4–7°C. The effects of chitosan on microbial proliferation, total volatile bases, nucleotide breakdown, and blackspot formation were monitored over this period. Chitosan showed strong antim…
Peroxo Fe(III), Mn(III), and Ti(IV) porphyrin complexes were reacted with a variety of electron-rich and electron-poor organic substrates in order to compare their reactivities with those of other known metalloperoxide complexes. The peroxoiron(III) porphyrin complex was unreactive with electron-rich substrates such a…
Single crystals of α‐Si 3 N 4 were annealed at 2000°–2150°C. The β phase was detected after annealing at 2150°C only when the crystals were surrounded by MgO·3Al 2 O 3 or Y 2 O 3 powders. On the other hand, no evidence of the α–β transformation was found when the crystals were annealed without additives. The solution–…
Lars Thorbjørn Jensen, Nis Baun Høst; Collagen: scaffold for repair or execution, Cardiovascular Research, Volume 33, Issue 3, 1 March 1997, Pages 535–539, http
Abstract This paper deals with a novel polyelectrolyte complex (PEC) of two natural polyelectrolyte ligands, i.e. chitosan (CS) and pectin (PTn). The composition and its effect on the swelling properties of this CS‐PTn PEC were studied. The results reveal that the swelling of the polyelectrolyte complex is connected w…
An isothiocyanate form of a lanthanide chelate which is highly luminescent when bound to terbium or europium has been synthesized. The chelate consists of diethylenetriaminepentaacetic acid (DTPA) covalently joined to a chromophore, 7-amino-4-methyl-2(1H)-quinolinone (cs124), and to L-p-aminophenylalanine, in which th…
Cu-ZSM-5 samples with various Cu(+)/Cu(2+) ratios have been successfully prepared in three different methods and studied by XPS and FTIR. Cu(+) ions are found, by XPS, to mainly exist in the samples prepared by solution ion exchange and microwave solid-state reaction exchange. On the basis of the chemical shift of the…
The Peierls stress is the stress required to move a dislocation through a perfect crystal lattice. Theoretical estimates show an exponential dependence on the ratio of the spacing between gliding planes and the unit slip distance. Nabarro corrected an error of a factor of 2 in this exponent in Peierls's original estim…
Magnetic and magnetoresistance measurements were carried out on a distorted perovskite, ${\mathrm{Eu}}_{0.58}$${\mathrm{Sr}}_{0.42}$${\mathrm{MnO}}_{3}$. In the absence of applied magnetic field, this compound is an insulator down to 5 K. Results of the ac- and dc-susceptibility measurements suggest a spin-glass groun…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTOxygen Surface Exchange and Diffusion in the New Perovskite Oxide Ion Conductor LaGaO3Tatsumi Ishihara, John A. Kilner, Miho Honda, and Yusaku TakitaView Author Information Department of Applied Chemistry, Faculty of Engineering Oita University, Dannoharu 700, Oita 870…
The hydrophilic/hydrophobic behavior of two silica polymorphs (a finely ground cristobalite and a pyrogenic amorphous Aerosil) was studied by means of adsorption microcalorimetry, as a function of nature and extension of the surface hydroxylated layer. Water and two alcohols (methanol and tert -butyl alcohol) were use…