Materials Literature
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Abstract A nonlinear dynamic model of a seeded potash alum batch cooling crystallizer is presented. The model of the batch crystallizer is based on the conservation principles of mass, energy and population. In order to maintain constant supersaturation, a nonlinear geometric feedback controller is implemented. It is…
The electronic structure of the Ruddlesden-Popper layered perovskite compound ${\mathrm{Sr}}_{3}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ is studied from density-functional calculations using the linear muffin-tin orbital method. An antiferromagnetic, insulating solution is obtained in agreement with the experiments, with a…
Ultrathin magnetic films are considered where the thickness-induced second order phase transition occurs due to surface magnetic anisotropy changes. By increasing the thickness, the easy magnetization axis state passes through the easy cone state (for film thickness t: t1 < t < t2) into the easy magnetization plane st…
Porphyrin quinones are attractive model compounds for mimicking natural electron transfer processes. While the overwhelming majority of studies have been performed with porphyrin p-quinones the isomeric porphyrin o-quinones have been mostly neglected. Using phenanthrene-9,10-quinones as the acceptor component we have…
Nitramide was investigated by multinuclear NMR spectroscopy, X-ray-diffraction and computational methods. The crystal structure analysis at various temperatures reveals a planar conformation of the molecule with a N-N bond length corresponding to a bond order between one and two. Hydrogen bonds connect the nitramide m…
This article presents experimental results for tensile creep behavior of orthogonal three‐dimensional woven Tyranno™ ZMI fiber/Si‐Ti‐C‐O ceramic matrix composites at 1300°–1450°C in air. The composite contained Tyranno ZMI (56% silicon, 1% zirconium, 34% carbon, and 9% oxygen) fibers with a BN coating layer to improve…
The effect of phosphate ions on the corrosion behaviour of copper in sulphate solutions was investigated at different temperatures (293, 313, 333, and 353 K) and at different pH values (pH = 2·1, 7·2, and 12·3). A three electrode electrochemical technique was used for the measurements, using a saturated calomel electr…
Cordierite-zircon ceramic composites were fabricated by die pressing a commercial cordierite powder with the addition of up to 10 wt-% zircon (ZrSiO4). Sintering of cordierite was enhanced by the ZrSiO4 addition through glass phase formation. With ZrSiO4 additions above 2·5 wt-% no further effect on the mechanical pro…
Compares the corrosion behaviour of Ti6Al4V titanium alloy, a conventional duplex stainless steel (UNS 31803) and AISI 304 austenitic stainless steel in synthetic biofluids using electrochemical techniques and comments on the suitability of DSS for use in biomedical applications. Finds that the general corrosion resis…
A potentiostatic weight loss technique has been used to compare the corrosion rates of Weldox 700 high strength low alloy steel exposed to both natural and sterile sea water at potentials ranging from the free corrosion condition to - 1000 mV (SCE). Anodic polarisation curves with Tafel constants of 54 and 64 mV per d…
The role of three key nitrogen regulatory genes, glnB (encoding the P(II) protein), glnZ (encoding the P(z) protein), and glnD (encoding the GlnD protein), in regulation of poly-3-hydroxybutyrate (PHB) biosynthesis by ammonia in Azospirillum brasilense Sp7 was investigated. It was observed that glnB glnZ and glnD muta…
Crystallization analysis fractionation (CRYSTAF) has been introduced for the analysis of the composition of polyolefin blends and the chemical composition distribution of polyolefins. Blends of syndiotactic and isotactic polypropylene (sPP and iPP) and of sPP/High density polyethylene (HDPE) have been fractionated by…
Complex studies of magnetic, electrical, and optical properties of V x Fe 1− x BO 3 solid solutions are carried out in the entire range of concentrations between the extreme compounds VBO 3 and FeBO 3 . A concentration semiconductor-insulator transition accompanied by a change in the magnetic structure is observed. It…
We examine optically induced birefringence in semicrystalline azopolymer films that are held at glass-transition temperature Tg. The birefringence increases markedly after interception of the pump beam; the saturation value depends on exposure time. In addition, the induced birefringence is completely erased by irradi…
The crystal structures of two square tetracyanocomplexes were determined. [Ni(dien)2][Ni(CN)4]·2H2O (NDNCH) and [Ni-(dien)2][Pd(CN)4] (NDPC) (dien = diethylene triamine) exhibit ionic structures consisting of mer-[Ni(dien)2]2+ cations and [Ni(CN)4]2- or [Pd(CN)4]2- anions, respectively. Moreover, the structure of NDNC…
Abstract The intercalation complex of a kaolinite from Cornwall, UK, with dimethylsulfoxide (DMSO) was studied by high-temperature X-ray diffraction (HTXRD), differential thermal analysis (DTA) and thermogravimetry (TG). The X-ray pattern obtained at room temperature indicated that intercalation of DMSO into kaolinite…
We consider the Lyapunov functional, of the rescaled Extended Fisher-Kolmogorov equation This is a fourth order generalization of the Fisher–Kolmogorov or Allen–Cahn equation. We prove that if ε → 0, then tends to the area functional in the sense of Γ-limits, where the transition energy is given by the one-dimensional…
Nicht nur hoch aktiv bei der Ethylenpolymerisation sind Bis(imino)pyridin-Eisen-Komplexe, sie katalysieren auch effizientes Kettenwachstum an Zinkzentren – formal eine eisenkatalysierte Aufbaureaktion am Zink (siehe Schema). Die erhaltenen Alkylketten können von den Zinkzentren durch eine Olefinaustauschreaktion verdr…
Two ferroelectric liquid crystals containing the naphthalene moiety were synthesized from 2(S)-[2(R)-methylhexyloxy]propionic acid and its (S, S)-diastereomer. Their mesogenic properties are compared with those of the analogous mesogens containing the biphenyl ring.
The cobalt(II) compounds ([Co(imid) 2 ] x (1), [Co(2-meimid) 2 ] x (2), [Co(4-meimid) 2 ] x (3), [Co(benzimid) 2 ] x (4), and [Co 3 (imid) 6 (imidH) 2 ] x (5) (imid = imidazolate, 2-meimid = 2-methylimidazolate, 4-meimid = 4-methylimi dazolate, benzimid = benzimidazolate)), have been synthesized and structurally and m…