Materials Literature
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2-Aza-21-carba-5,10,15,20-tetraarylporphyrin (CTPPH 2, inverted porphyrin) and its methylated derivatives, acting as ligands, can be structurally related to the following hypothetical tautomers: 2-aza-5,10,15,20-tetraphenyl-21-carbaporphyrin (2-NH-CTPPH); 2-aza-5,10,15,20-tetraphenyl-21-methyl-21-carbaporphyrin (21-H-…
Article A rational approach to the mechanisms of incrustation inhibition by polymeric additives / Wirkungsweise von polymeren Inkrustrationsinhibitoren was published on December 1, 1997 in the journal Tenside Surfactants Detergents (volume 34, issue 6).
We investigate the compatibilizing performance of a random copolymer in the melt state, using transmission electron microscopy. Blends of polystyrene (PS) and poly(methyl methacrylate) (PMMA) are chosen as a model system, and a random copolymer of styrene and methyl methacrylate (SMMA) with 70 wt % styrene is used as…
Ceramic samples of Ce 1− x Gd x O 2− y and yttria‐stabilized zirconia (YSZ) were prepared using solid‐state methods. Polished faces of disks of these materials were held in intimate contact in a reaction cell at temperatures ranging from 1000° to 1300°C for durations up to 72 h. XRD, SEM, and microprobe Raman techniqu…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTDivergent/Convergent Joint Approach with a Half-Protected Initiator Core To Synthesize Surface-Block DendrimersKeigo Aoi, Katsuhito Itoh, and Masahiko OkadaView Author Information Department of Applied Biological Sciences, Faculty o…
The corrosion behavior and strength degradation of alumina ceramics with 99%, 99.9%, and 99.99% Al 2 O 3 were studied in water at 300°C and 8.6 MPa for 1 to 10 d. The weight loss in alumina ceramics was mainly attributed to the dissolution of SiO 2 and Na 2 O grain‐boundary impurities. Intergranular corrosion proceede…
Fiber pushout tests were used to quantify the effects of fiber coating thickness on the mechanical properties of two model composite systems: a monazite‐coated (LaPO 4 ‐coated) alumina (Al 2 O 3 ) fiber in an Al 2 O 3 matrix and a LaPO 4 ‐coated yttrium aluminum garnet (YAG) fiber in an Al 2 O 3 matrix. Interface prop…
A model asphalt has been separated into two parts, asphaltene and maltene, through solvent extraction by n-heptane. The interactions of asphaltene and maltene with the triblock copolymer poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) were investigated by transmission electron microscopy (TEM), small-angle X-r…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTPolymeric Organic−Inorganic Hybrid Nanocomposites: Preparation of Polyimide-Modified Poly(silsesquioxane) Using Functionalized Poly(amic acid alkyl ester) PrecursorsJ. L. Hedrick, H.-J. Cha, R. D. Miller, D. Y. Yoon, H. R. Brown, S. Srinivasan, R. Di Pietro, R. F. Cook, J. P. H…
1 H NMR imaging has been used to monitor the enzymatic degradation of poly(3-hydroxybutyrate), PHB, and poly(3-hydroxybutyrate- co -23%-3-hydroxyvalerate), PHB/V, by PHB depolymerase B from Pseudomonas lemoignei . The samples examined were thin films of approximately 200 μm thickness produced by melt casting. Since on…
Previous studies from our laboratory have shown that deletion of residues 321 to 344 of the 9-2 isozyme of 2'-5'-oligoadenylate (2-5(A)) synthetase causes a loss of its enzyme activity (Ghosh, S. K., Kusari, J., Bandyopadhyay, S. K., Samanta, H., Kumar, R., and Sen, G. C. (1991) J. Biol. Chem. 266, 15293-15299). Seque…
We discuss spin and orbital ordering in the twofold orbital degenerate superexchange model in three dimensions relevant to perovskite transition metal oxides. We focus on the particular point on the classical phase diagram where orbital degeneracy is lifted by quantum effects exclusively. Dispersion and damping of the…
Abstract Electrically conductive polymer blends can be prepared by in situ polymerization of pyrrole within another polymer matrix. This may be accomplished using either electrochemical or chemical oxidative polymerization. This paper reviews the literature on this subject.
Micro-Raman spectra for PbZrxTi1—xO3 (PZT) with grain sizes of 60 and 40 nm have been obtained. The results show that the E(TO1) phonon mode of PbTiO3 (‘soft’ mode) displays a decrease in frequency and an increase in linewidth with increasing Zr concentration. A discontinuous behavior in the phonon energy for the soft…
Abstract Polypropylene (PP) composites were prepared with a constant volume fraction of a CaCO 3 filler, which was treated with eight trialkoxy functional silane coupling agents and the routinely used stearic acid, as comparison, The tensile properties of the composites were determined as a function of surface coverag…
In Escherichia coli, flavodoxin is the physiological electron donor for the reductive activation of the enzymes pyruvate formate-lyase, anaerobic ribonucleotide reductase, and B12-dependent methionine synthase. As a basis for studies of the interactions of flavodoxin with methionine synthase, crystal structures of ort…
The influence of resonance on the structure and rotation barrier of formamide and its S, Se, and Te replacements analogues is examined using the natural bond orbital methods. Calculations are performed at the RHF, B3LYP, and MP2 levels of theory with 6-31+G* basis sets and effective core potentials. At the MP2 level,…
Molecular differential cross sections for the coherent scattering of x-rays in polymethyl methacrylate (PMMA) and fat were determined from measured diffraction patterns in the interval chi = 0 to 6.4 nm-1 (chi = [sin theta/2)]/lambda; lambda being the incident wavelength having the units of nm and theta the scattering…
The nonlinear optical (NLO) properties at the molecular level of a family of unsymmetrically substituted metal-free phthalocyanines ( 3 − 9 ) have been studied for the first time. NLO characterization has been performed by electric field-induced second harmonic (EFISH) generation and third harmonic generation (THG) ex…
The sol‐gel synthesis technique has been used to produce barium ferrite particles. Several methods such as X‐ray diffractometry, transmission electron microscopy, and magnetism measurement (VSM) have been used to obtain detailed information on the crystallography and magnetic properties of the precursor and the calcin…