Materials Literature
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In colossal magnetoresistance materials, ferromagnetic double exchange presumably coexists with a direct nearest-neighbor antiferromagnetic interaction. We construct a single-site mean-field theory that explicitly takes into account the different nature of carrier-mediated ferromagnetism vs Heisenberg-like superexchan…
Principles of solid-state structure and bonding that relate metal-halide and metal-chalcogenide materials are described through a comparison of binary AX n salts. Structural variation is rationalized by a comparison of the size and charge of the respective ions, the d-electron count of the cations, and the type of A−X…
This paper studies the dye-sensitized photooxidation of tyrosine (tyr) and tyr di- and tripeptides (tyr-tyr and tyr-tyr-tyr) mediated by singlet molecular oxygen (O2[1 delta g]) in alkaline media. Photooxidation quantum efficiencies (phi r) were obtained by determining the overall and reactive rate constants of intera…
Ring-opening reactions of 1,3-dioxepan-2-one (1) and 1,3-dioxan-2-one (2) with several alcohols were examined. The reactions proceeded without trifluoroacetic acid (TFA) in low conversions, while they proceeded smoothly with TFA to afford the ring-opened adducts and oligomers. Ring-opening polymerizations of 1 and 2 w…
Identification of the metal-containing products of reactions of the neutral transition metal atom Zr(4d 2 5s 2, 3 F) with ethylene and propylene is accomplished using one-photon ionization at 157 nm and time-of-flight mass spectrometry. The reactions proceed in a fast flow reactor at 298 K with He/N 2 buffer gas at 0.…
Double emulsions are emulsion-within-emulsion systems with promising applications. Attempts have been made to find new amphiphiles to improve their thermodynamic stability and to control the release of active matter or markers from double emulsions. The present review summarizes our efforts to study the mechanisms of…
The effect of a near-bottom transport scheme on the sensitivity of the thermohaline circulation is analyzed in a coupled model. In this model with idealized geometry of the Atlantic, it is shown that in the presence of a northern source of deep water, an accurate representation of the overflow process has a stabilizin…
The Escherichia coli surE gene is co-transcribed with pcm, encoding the L-isoaspartyl protein repair methyltransferase, and is highly conserved among both the Eubacteria and the Archaea; however, no biochemical function has yet been identified for this gene. Isoaspartyl accumulation during stationary phase was much hi…
During the wet oxidation of contaminated wastewaters, the destruction of low molecular weight carboxylic acid intermediates such as acetic, glyoxalic, and oxalic acids is often the rate-controlling step. Oxidation of acetic acid, a very recalcitrant intermediate, requires compelling treatment severity. Heterogeneous c…
Lithium silicophosphate glasses have been prepared by a sol−gel route over a wide range of compositions. Their structural and electrical properties have been investigated. Infrared spectroscopic studies show the presence of hydroxyl groups attached to Si and P. MAS NMR investigations provide evidence for the presence…
Luminescent silicon clusters have been synthesized by the chemical vapor deposition of Si 2 H 6 into the α-cages of H 32 Na 24 Y zeolite. The synthetic process was monitored by FTIR, TGA-MS, and 29 Si and 1 H solid-state NMR spectroscopies. In the initial step at 100 °C, Si 2 H 6 reacts with the Brønsted acid sites to…
The kinetic studies of the crosslinking reaction of a nadic end-capped imide model compound, N,N′-(oxydi-3,4′-phenylene) bis(5-norbornene-2,3-dicarboximide), a bisnadimide, in thermal and microwave processes were investigated. The conversion of the endo isomer to exo isomer proceeds at a much lower temperature than th…
We have carried out ab initio molecular orbital calculations on a cluster of atoms containing five SiO 3/2 O - Na + units connected at the corners by siloxane bonds to investigate the structure and vibrational properties of sodium disilicate glass. The optimized structural parameters (mean Si−O, O−O, and Na−O bond dis…
The effect of surfactants on single-bubble sonoluminescence (SBSL) is studied theoretically based on the hot-spot model that a SBSL bubble collapses quasiadiabatically and that the quasi-thermal radiation is the origin of the light emission. Stottlemyer and Apfel [J. Acoust. Soc. Am. 102, 1418 (1997)] reported that th…
Polycrystalline indium-tin-oxide (ITO) thin films were prepared at an ambient temperature by irradiation of amorphous (a-) ITO with KrF excimer laser pulses of ≥40 mJ/cm 2 /pulse. Electrical resistivity of the specimen at ∼300 K decreased from 5.9×10 -4 Ω·cm to 2.7×10 -4 Ω·cm upon laser crystallization. Irradiation of…
The effect of grain size on the colossal magnetoresistance mechanism is analyzed. While the metal-insulator transition temperature ${T}_{R\mathrm{max}}$ is markedly affected by the grain size, the magnetic transition temperature ${T}_{c}$ is not sensitive to the grain size. It is found that the surface phonon plays an…
The electrostatic binding of the anionic probes pyrenetetrasulfonic acid (4-PSA) and 6-carboxyfluorescein (6-CF) to poly(allylamine hydrochloride) (PAH), poly(diallyldimethylammonium chloride) (PDADMAC), and DADMAC−acrylamide (AAM) copolymers in aqueous solution has been investigated by fluorescence spectroscopy. Bind…
Evidence is accumulating for the major influence of the identities of counterions on syntheses and properties of various heteropoly anions. An easy and convenient NMR method is presented for evaluating the extent of significant association between heteropoly tungstate species and monoatomic metallic counterions (e.g.,…
Raman spectroscopy of two types of kaolinites has been obtained at liquid nitrogen temperature (77 K) with the use of a Raman microprobe and a thermal stage. The Raman spectrum is characterized by the combination of the frequencies of the inner hydroxyl and the inner surface hydroxyl groups. The inner hydroxyl frequen…
The interfacial reinforcement between polypropylene (PP) and amorphous polyamide (aPA) has been investigated by in-situ reactive compatibilization. PP reactivity with aPA was introduced by melt blending a certain amount of maleic anhydride grafted polypropylene (mPP) with pure PP. The effects of the mPP content, bondi…