Materials Literature
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A high-pressure differential scanning calorimetric technique is described for studying polymer plasticization by compressed gases at pressures to 100 atm. The in situ measurements avoid problems due to gas desorption encountered with conventional DSCs, thus providing an accurate way to determine the change in glass tr…
The self-condensing vinyl polymerization of 4-(chloromethyl)styrene using metal-catalyzed living radical polymerization catalyzed by the complex CuCl/2,2′-bipyridyl has been attempted. Given the unequal reactivity of the two potential propagating species in this system, a variety of polymerization conditions were test…
Mesoporous titania and niobia molecular sieves were prepared by a ligand-assisted templating method. For comparison, titania samples were also prepared by simple hydrolysis and condensation of Ti alkoxide in the absence of templating agents. All materials were thoroughly characterized by UV−vis reflectance spectroscop…
Red and yellow soils from tropical regions are generally more mature than their subtropical counterparts. Most of these soils contain kaolin as the dominant clay mineral. Exchangeable aluminium (Al) generally balances permanent negative charges and occupies strongly acidic exchange sites of the soil clay. The objectiv…
The trinuclear compound [dmbReI(CO)3-bpy-RuIII(en)2NCFeIII(CN)5]Br was synthesized and characterized by UV/vis and IR spectroscopy. Irradiation of this complex in the presence of added phenothiazine leads to a mixed-valence Re(I)−Ru(III)−Fe(II) photoproduct and PTZ•+. Several possible photochemical processes are propo…
The mixed-valence molecule Sn II Sn IV (O i Pr) 6 is conveniently synthesized and is shown to exchange bridging and terminal alkoxides in solution in its Sn(μ-O i Pr) 3 Sn(O i Pr) 3 structure. Pb 3 SnO(O i Pr) 8 is synthesized and shown to undergo an intramolecular fluxional process in solution. Both molecules are suf…
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…