Materials Literature
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A novel heterocyclic diamine monomer, 2-(4-aminophenyl)-6-amino-4(3 H )-quinazolinone was synthesized from readily available compounds in three steps in high yield. A series of novel polyimides containing the quinazolinone moiety were synthesized either by a one-step solution polymerization reaction or by a two-step p…
This article contains (i) an experimental EPR study on [4Fe−4S] 3+ and [4Fe−4S] + centers in single crystals of a model compound having an asymmetrical cubane-type cluster and (ii) a theoretical model for the interpretation of g -tensors of such states found in synthetic compounds and protein active sites. In the firs…
Samples of highly syndiotactic polypropylene (s-PP), when quench precipitated from solution, have an X-ray diffraction spectrum close to that calculated for the limit-ordered C 222 1 form II of s-PP. The solid state 13 C NMR CP MAS spectrum shows, however, evidences of the presence of a significant amount (≈20%) of lo…
Abstract The structure of Li- and Cs-montmorillonites was studied using infrared (IR) reflectance spectroscopy. The spectra of heat-treated clays between 80 and 220 °C were analyzed by Kramers-Krönig inversion in order to obtain the optical and dielectric properties of the clays. The analysis revealed the transverse-o…
Magnetic properties of two nitronyl nitroxide (4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide) radicals which show nearly isotropic S=½ alternating linear chains are investigated down to 0.5 K and up to 9 T. Pentafluorophenyl nitronyl nitroxide at low temperatures shows an antiferromagnetic chain with alte…
Vacuum drying and especially discontinuous vacuum drying is a very attractive process for such a wood as oak, because of a reduced drying time and a high quality of the final product. In this paper, a model describing heat, mass and momentum transfer in a capillary porous and hygroscopic medium under vacuum drying wit…
Bien que beaucoup de questions soient resolues en ce qui concerne l'oxydation acceleree des super alliages par les depots de sels corrosifs, il reste encore quelques questions sans reponses. La composition chimique du sel de mer qui entre dans les moteurs est differente de celle des sels qui adherent aux composants de…
A study of plastic instability in tension, which occurs well before the Considère criterion is met, is reported for face-centred cubic single crystals. The observations show that the instability is caused by a sudden effective decrease in work hardening resulting from the operation of a new dominant shear system. The…
The structures and characterization are described of complexes that exhibit an out-of-phase AC magnetic susceptibility x m” The dodecanuclear complexes [Mn12O12(O2CR)16(H2O)4]z contain 8MnIII, 4MnIV or MnII, 7MnIII, 4MnIV and possess ground state spins of S = 9 or 10 (z = 0) or S = 19/2 (z = −1). The distorted-cubane…
Abstract Non‐elastic deformation of amorphous polymers is studied from strain recovery tests. In particular, a strain recovery master curve is built. It allows one to estimate recovery times necessary to recover the whole non‐elastic deformation. On such a curve, two non‐elastic deformations, namely anelastic (nonline…
Novel regular network polyesters were prepared from pentaerythritol (Xp) and aliphatic dicarboxylic acids of different numbers of methylene groups (HOOC(CH 2 ) n - 2 COOH, n = 4, 6, 8, 9, 10, 12, 14, 16, and 20). Prepolymer prepared by melt polycondensation was cast from dimethylformamide solution and postpolymerized…
Abstract Common and different aspects of scanning electron microscope (SEM) and scanning ion microscope (SIM) images are discussed from a viewpoint of interaction between ion or electron beams and specimens. The SIM images [mostly using 30 keV Ga focused ion beam (FIB)] are sensitive to the sample surface as well as t…
Boron carbide pellets were irradiated in the experimental fast reactor “JOYO” to 10B burnup of up to 170x1026cap/m3, fluences of 2x1026/m2(E>0.1MeV), and maximum temperatures of about 1,200°C. Post irradiation examinations were made of microstructural changes, helium release, swelling, and thermal conductivity. Boron…
The static properties of a homopolymer melt between energetically neutral walls are studied as a function of the degree of confinement (plate spacing) and polymer molecular weight. The cooperative motion lattice model is used and allows all calculations to be performed at full occupancy (i.e., at a volume fraction of…
The decomposition of aqueous ammonium nitrate at elevated temperatures and pressures is examined as a function of chloride, nitrate, and total acidity. Catalysis requiring both chloride and acid was observed in solutions containing 20% (w/w) NH 4 NO 3 at 180 °C. Nitrous oxide and dinitrogen were generated in a 4:1 rat…
The nature of analyte species collected on a cooled silica tube for atom-trapping atomic absorption spectrometric determination was investigated with the use of X-ray photoelctron spectroscopy (XPS). An XPS spectrum of gold deposited on atom-trapping silica tubes reveals a Au 4f 7/2 peak with a binding energy of 84.8…
Pronounced electron–phonon coupling is observed for the F7/22↔F5/22 4f transitions of Yb3+ doped into CsCdBr3. A comparison of the Raman spectrum and the luminescence excitation sideband accompanying the F7/22(0)→2F5/2(2′) crystal-field transition reveals vibrational properties of the [YbBr6] coordination unit that di…
The corrosion rates of mild steel in a neutral aqueous environment containing 60 ppm C1 ‐ in the absence and presence of the sodium salt of amino (trimethylene phosphonic acid) (ATMP), polyacrylamide (PAA) and Zn 2+ have been evaluated by the classical weight‐loss method. The formulation consisting of 50 ppm PAA and 5…
The atomic and electronic structure and other structural properties of the metastable \ensuremath{\kappa} phase of ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ have been investigated with a first-principles total-energy method based on density-functional theory at the local-density-approximation level, plane waves, and pseudop…
Copolymerization reactions between cyclic(arylene disulfide) oligomers were studied. The cyclic disulfide oligomers derived from 4,4′-isopropylidene bisbenzenethiol gave soluble polysulfanes via copolymerization with S8. The copolymerization reactions were studied both in solution and melt by GPC and NMR. Solution cop…