Materials Literature
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Abstract A new hyperbranched poly(phenylene oxide) was synthesized from a simple AB 2 type monomer, 3,5‐dibromophenol, by Ullmann polycondensation. The bromo‐terminated hyperbranched poly(phenylene oxide) was amorphous ( T g = 120 °C), but showed high thermal stability ( T 5d = 480 °C in nitrogen). The polymer with th…
Abstract This paper describes the 70/30 wt% composition of SAN/PA6 blends having different types of morphology, namely PA6 dispersed in SAN, a co‐continuous structures of PA6 and SAN, and a “mixed structure” which exhibits PA6 particles in SAN which themselves form the matrix for smaller SAN particles. These morpholog…
Cytochrome c can be readily adsorbed onto mesoporous silicates at high loadings of up to 10 mmol g(-)(1) of silicate. The adsorbed protein retains its peroxidative activity, with no diffusional limitations being observed. The protein can be adsorbed onto the external surface of the silicate or, provided that the pore…
Nous avons affine la structure cristalline de l'argentojarosite naturelle, dont la formule ideale est AgFe 3 (SO 4 ) 2 (OH) 6 , a 7.3398(7), c 16.538(3) A, V 771.4(2) A 3 , groupe spatial R3m, Z= 3, jusqu'a un residu R 1 de 2.8% sur une base de 307 reflexions uniques mesurees avec rayonnement MoKa et un diffractometre…
This work reports studies on the electrochemical behavior of AB5-type hydrogen storage alloys, formed by LaNi(5-x)Zx, where Z is a metallic element partially replacing Ni, which included Sn, Al, Mn, and Pd. In the case of Mn, some AB6-type structures were also considered. Substitution of a small fraction of Ni by Al,…
Abstract In the present paper the potential use of hyperbranched (HB) aramids as metallic solution stabilisers and carriers for homogeneous catalysis is outlined. Aramids, synthesised either from A 2 + B 3 reagents [namely, p ‐phenylenediamine (PPD) and trimesic acid (TMA)] or from an AB 2 monomer [i.e., 5‐(4‐aminoben…
Dendrimers can be obtained in precise molecular weights even at high generations. This feature, as well as the inherent globular shape of high generation dendrimers, makes them ideal candidates for macromolecular biomimetics. In this account, we discuss the synthesis and use of dendrimers that are reminiscent of macro…
This manuscript highlights the various dendritic effects reported in the literature.
For industrial chemical processes, it would be highly desirable from both a commercial and an environmental point of view to incorporate the advantages of homogeneous and heterogeneous catalysis into one chemical process. The ultimate goal is to design a catalytic system with the high activity and selectivity of homog…
The cooperative phenomena revealed in the field and temperature dependences of the magnetization in a system of iron nanoparticles in carbon nanotubes were studied experimentally. The character of the temperature dependences of the magnetization indicates that the ferromagnetic Fe particles in carbon nanotubes are exc…
Thermodynamic calculations were conducted to understand the carburizing environment of ethylene industries. The equilibrium PO2 was calculated to be from 10–21 atm to 10–19 atm for the operating conditions of the actual furnace tubes from 900°C to 1,100°C. In this environment, protective chromium oxide (Cr2O3) scale w…
We elaborate an analytical theory of a cascade of magnetic field-induced charge-density-wave (FICDW) phases. It is shown that the following features distinguish it from the well-known spin-density-wave cascade: (1) the FICDW phases exist at temperatures much lower than the characteristic CDW transition temperature at…
From 57Fe Mössbauer measurements carried out on the spinel ferrite under study, the ratio of the integrated intensities of 57Fe A- and B-site subspectra can be evaluated. The composition of the ferrite has been established as (Fe3+)[Ni2+Cr3+xFe3+1−x] for 0.0 ≤ x ≤ 0.6. The composition dependence of the Mössbauer hyper…
Abstract Mixtures of epoxy resins in the presence of epoxy hyperbranched polymers (HBP), in the range of 5–15 wt%, were investigated in the cationic photocuring process. No significant differences in rate of polymerization or final epoxy groups conversion were observed. At low concentration, HBP acts as plasticizer an…
Intermetallic formation at 425°C in the aluminum–copper system has been studied by scanning electron microscopy using welded diffusion couples. Several Al–Cu phases predicted by the equilibrium phase diagram of the elements and voids taking place in the diffusion zone have been detected in the couples. The predominant…
Aggregates of oxygen vacancies (F centers) represent a particular form of point defects in ionic crystals. In this study we have considered the combination of two oxygen vacancies, the M center, in the bulk and on the surface of MgO by means of cluster model calculations. Both neutral and charged forms of the defect M…
Abstract A multiple charge‐transfer second‐order nonlinear optical (NLO) chromophore 2,3‐bis(4‐aminophenyl)‐5,6‐dicyanopyrazine (BAPDCP) was successfully designed and synthesized. It was characterized by 1 H NMR, mass spectrometry, Fourier transform infrared spectroscopy, and elemental analysis. The first hyperpolariz…
Abstract The colourless title compound scandium(III) oxoselenate‐(IV) Sc 2 Se 3 O 9 (≡Sc 2 [SeO 3 ] 3 ) was obtained by reacting a 1:3‐molar mixture of Sc 2 O 3 and SeO 2 at 830°C for seven days in an evacuated torch‐sealed silica vessel as needle‐shaped single crystals. It crystallizes hexagonally (space group: P6 3…
RATIONALE AND OBJECTIVES: To evaluate 4 doses of gadobenate dimeglumine (Gd-BOPTA) for contrast-enhanced magnetic resonance angiography (CE-MRA) of the pelvic arteries and to compare CE-MRA with unenhanced time-of-flight MRA (2D-TOF-MRA). METHODS: A multicenter Phase II dose-finding study was performed in 136 patients…
There has been recent interest in photoinduced chirality in azo polymers upon irradiation with circularly polarized light. The mechanism of ordering is thought to involve successive twisting of the achiral photoactive azo-containing side chains in response to the handedness of the pump polarization. In this study, a t…