Materials Literature
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Very sandy and sometimes seasonally inundated humus podzols of the Bassendean soil association in southwest Australia experience severe leaching of fertiliser P with consequent eutrophication of waterways. P sorption by these soils is mostly minimal and is primarily due to the podzol Bh horizon. The consequence of sea…
Scattering experiments were conducted on a critical, binary mixture of polyethylene (PE) and head-to-head polypropylene (PP), and a symmetric PE−PP diblock copolymer melt. The binary mixture exhibited a liquid−liquid phase transition at 143 °C, while the block copolymer exhibited an order−disorder transition at 149 °C…
Three compounds, BaDyCuTe 3, K 1.5 Dy 2 Cu 2.5 Te 5, and K 0.5 Ba 0.5 DyCu 1.5 Te 3, were synthesized from the reaction at 850 °C of the pure elements with fluxes such as BaCl 2 or a eutectic mixture of LiCl/KCl. The crystal structures of the three compounds were determined by the single-crystal X-ray method. The fina…
Plasma-induced low-density polyethylene (LDPE) radicals were studied in detail by electron spin resonance (ESR) by its comparison with ESR of high-density polyethylene (HDPE). The observed ESR spectra of plasma-irradiated LDPE are largely different in pattern from those of HDPE. The systematic computer simulation disc…
Electronic aspects of an iron porphyrin, 5,10,15,20-tetrakis(4-methoxyphenyl)-21 H,23 H -porphine iron(III) chloride (FeTMPPCl) molecularly dispersed on a high area carbon black (Black Pearls 2000, BP) and then heat-treated (or thermally activated) at 800 °C in a flowing inert atmosphere, were investigated in situ in…
We analyze the stability of a planar solid-solid interface at which a chemical reaction occurs. Examples include oxidation, nitridation, or silicide formation. Using a continuum model, including a general formula for the stress-dependence of the reaction rate, we show that stress effects can render a planar interface…
The validity of the adiabatic approach to spin-Peierls transitions is assessed. An alternative approach is developed which maps the initial magneto-elastic problem to an effective magnetic problem only. Thus the equivalence of magneto-elastic solitons and magnetic spinons is shown. No soft phonon is required for the t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPreparation of Cu Nanoclusters within Dendrimer TemplatesMingqi Zhao, Li Sun, and Richard M. CrooksView Author Information Department of Chemistry, P.O. Box 300012 Texas A&M University, College Station, Texas 77842-3012 Cite this: J. Am. Chem. Soc. 1998, 120, 19, 4877–…
A series of molybdena catalysts supported on anatase titania with Mo loadings ranging from 2 to 12 wt % were investigated by 1 H MAS NMR, XRD, ESR, and oxygen chemisorption. 1 H MAS NMR spectra reveals the presence of two types of OH groups (acidic and basic) on TiO 2 . Dispersion of molybdena was determined by the ox…
A robust trigonal prismatic cluster anion [Pt 3 (CO) 6 ] 5 2- (ν CO = 2078, 1878 cm -1; λ max = 405 and 702 nm; R 1 (Pt−Pt) = 2.68 Å (CN = 2.0); R 2 (Pt−Pt) = 3.08 Å (CN = 1.5)) is selectively synthesized in the ordered hexagonal channel of FSM-16 by the reductive carbonylation of H 2 PtCl 6 /NR 4 + /FSM-16 under a CO…
Four unsymmetrical covalently linked porphyrin dimers were synthesized, and their electrochemical, spectroelectrochemical, and/or photophysical properties were examined. The investigated compounds are represented as M[ p -(TPP-DEHMP)]M and M[ m -(TPP-DEHMP)]M (M = H 2, Zn), where p -(TPP-DEHMP) is the tetraanion of 1-…
This paper discusses the dynamic interfacial tension (IFT) variation in a system containing an acidic oil in contact with an alkaline solution which may contain a preformed surfactant. A modified technique similar, in principle, to the sessile drop technique is used for monitoring the dynamic IFT which is in the ultra…
The structure of QUI-MnGS-1 has been determined from single-crystal X-ray diffraction on a ∼0.03 × 0.03 × 0.02 mm sample using synchrotron radiation. This material [(C 7 H 13 N)Mn 0.25 Ge 1.75 S 4 ·H 2 O] crystallizes in space group I 4̄2 d with unit cell a = 11.581(1) and c = 18.741(3) Å. The extended framework of th…
The compound Cs 3 Te 22 is well-known for its interesting structural features. It contains both a unique 2,3-connected defect square Te sheet and Te 8 rings. For a better understanding of the structure and bonding, the band structure of Cs 3 Te 22 is examined by means of the ab initio tight-binding linear muffin-tin o…
The phase diagram of a protein−water system is described with a simple model with parameters for the interaction between protein molecules in the liquid and in the solid phase. The model reproduces essential features of the phase diagram, such as the (metastable) liquid−liquid immiscibility region and the triple point…
A pair of tropinone reductases (TRs) share 64% of the same amino acid residues and belong to the short-chain dehydrogenase/reductase family. In the synthesis of tropane alkaloids in several medicinal plants, the TRs reduce a carbonyl group of an alkaloid intermediate, tropinone, to hydroxy groups with different diaste…
As part of a structure-aided effort to design clinically useful inhibitors of metallo-beta-lactamases, the X-ray crystal structure of a complex between the metallo-beta-lactamase from Bacteroides fragilis and 4-morpholinoethanesulfonic acid (MES) has been determined and a model for the structure has been refined to a…
A series of benzyl-substituted phthalonitriles, substituted at the 3-, 4-, and 4,5-positions, underwent varied condensations with phthalonitrile to give a series of protected (monohydroxy- and polyhydroxyphthalocyaninato)zinc(II) derivatives which were readily cleaved to give several hydroxyphthalocyanines (ZnPc) (pht…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDerivatization of Porous Silicon by Grignard Reagents at Room TemperatureNamyong Y. Kim and Paul E. LaibinisView Author Information Departments of Chemistry and Chemical Engineering Massachusetts Institute of Technology Cambridge, Massachusetts 02139 Cite this: J. Am.…
The crystal structure of syndiotactic polystyrene (sPS) in its stable α form (a so-called “superstructure” named α‘‘) is reevaluated. As shown by all previous investigations, the trigonal unit cell contains three triplets of extended sPS chains. The azimuthal orientation of the three triplets is shown to differ from t…