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131.
The addition of water vapor has a strong positive effect on the rate of ethane oxidation at 575°C. This effect is attributed to the role of H2O as a third body in the decomposition of H2O2 to OH radicals. Carbon tetrafluoride likewise enhances the rate of ethane conversion, although not to the extent realized with H2O. A kinetic model, based on known elementary reactions, adequately accounts for the conversions and selectivities observed as a function of H2O pressure, temperature, contact time, and O2 pressure. © 1994 John Wiley & Sons, Inc. 相似文献
132.
This paper reports a new layer-by-layer assembly approach to fabricate multilayers of cofacially aligned porphyrins on solid supports by a selective siloxane formation utilizing tetraphenylporphyrinatosilicon(IV) chloride as the building block. 相似文献
133.
M.?Cristina?Gon?alves Verónica?de?Zea Bermudez M.?M.?Silva M.?J.?Smith Enrique?Morales Rute?A.?Sá Ferreira Luís?D.?Carlos 《Ionics》2010,16(3):193-201
Variable chain length di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks were prepared by application
of a sol-gel strategy. These materials, designated as di-urethanesils (represented as d-Ut(Y′), where Y′ indicates the average
molecular weight of the polymer segment), were doped with lithium triflate (LiCF3SO3). The two host hybrid matrices used, d-Ut(300) and d-Ut(600), incorporate POE chains with approximately 6 and 13 (OCH2CH2) repeat units, respectively. All the samples studied, with compositions ∞ > n ≥ 1 (where n is the molar ratio of (OCH2CH2) repeat units per Li+), are entirely amorphous. The di-urethanesils are thermally stable up to at least 200 °C. At room temperature the conductivity
maxima of the d-Ut(300)- and d-Ut(600)-based di-urethanesil families are located at n = 1 (approximately 2.0 × 10−6 and 7.4 × 10−5 Scm−1, respectively). At about 100 °C, both these samples also exhibit the highest conductivity of the two electrolyte systems
(approximately 1.6 × 10−4 and 1.0 × 10−3 Scm−1, respectively). The d-Ut(600)-based xerogel with n = 1 displays excellent redox stability. 相似文献
134.
D. Mendoza J.L. Benítez F. Morales R. Escudero 《Solid State Communications》2010,150(25-26):1124-1127
Synthesis, electrical and magnetic characterization of a superconducting FeSe0.85 compound is reported. An anomaly in the magnetization against temperature around 90 K is observed. The magnetic characterization of a commercial compound with nominal FeSe stoichiometry is also presented. The overall magnetic behaviors as well as the magnetic anomaly in both compounds are discussed in terms of magnetic impurities and secondary phases. 相似文献
135.
G. Gomez-Rosas C. Rubio-Gonzalez C. Molpeceres M. Morales 《Applied Surface Science》2010,256(20):5828-5831
Laser Shock Processing (LSP) has been proposed as a competitive alternative technology to classical treatments for improving fatigue and wear resistance of metals. We present a configuration and results in the LSP concept for metal surface treatments in underwater laser irradiation at 532 nm and 1064 nm. The purpose of the work is to compare the effect of both wavelengths on the same material. A convergent lens is used to deliver 1.2 J/pulse (1064 nm) and 0.9 J/pulse (532 nm) in a 8 ns laser FWHM pulse produced by 10 Hz Q-switched Nd:YAG laser with spots of a 1.5 mm in diameter moving forward along the work piece. A LSP configuration with experimental results using a pulse density of 2500 pulses/cm2 and 5000 pulses/cm2 in 6061-T6 aluminum samples are presented. High level compressive residual stresses are produced using both wavelengths. It has been shown that surface residual stress level is comparable to that achieved by conventional shot peening, but with greater depths. This method can be applied to surface treatment of final metal products. 相似文献
136.
C. A. Morales 《Monatshefte für Mathematik》2010,159(3):253-260
We define sectional-Anosov flow as a vector field on a manifold, inwardly transverse to the boundary, whose maximal invariant set is sectional-hyperbolic (Metzger and Morales in Ergodic Theory Dyn Syst 28:1587–1597, 2008). We obtain properties of sectional-Anosov flows without null-homotopic periodic orbits on compact irreducible 3-manifolds including: incompressibility of transverse torus, non-existence of genus 0 transverse surfaces nor hyperbolic attractors nor hyperbolic repellers and sufficient conditions for the existence of singularities non-isolated in the nonwandering set. These generalize some known facts about Anosov flows. 相似文献
137.
The thermal chemistry of 1-methyl-1-cyclopentene (1MCp(=)) and methylene cyclopentane (MeCp) was investigated on clean and hydrogen- and deuterium-predosed Pt(111) single-crystal surfaces by temperature-programmed desorption and reflection-absorption infrared spectroscopy. It was found that MeCp isomerizes easily to 1MCp(=) but that the reverse reaction does not occur, at least under our experimental conditions. The MeCp to 1MCp(=) isomerization is aided by the presence of coadsorbed hydrogen, and occurs through the formation of a common 1-methyl-1-cyclopentyl (1MCp-Pt) surface intermediate; that intermediate then undergoes beta-hydride elimination selectively at the ring position to form the 1MCp(=) product. In addition to this isomerization, both 1MCp(=) and MeCp also dehydrogenate on the Pt(111) surface to form a methylcyclopentadiene species, at 325 and 350 K, respectively. A small amount of benzene desorption is detected above 500 K with both reactants, indicative of a ring enlargement reaction. No evidence for the activation of any of the allylic hydrogens was obtained in either molecule. 相似文献
138.
139.
The current study focuses on the status of automation and mechanization in spectroscopy for analytical chemistry publications compiled during the period 1980–2006, in Analytical Abstracts. Flow injection analysis (FIA), sequential injection analysis (SIA), multicommutation, and monosegmented and segmented flow strategies were considered. For assessing the evolution of scientific productivity, the total number of publications concerned with the different methodologies was evaluated. In order to provide a picture of the state of the art of this field, the most important journals, the most active authors, and the most productive countries in the field of automation were evaluated in the period of the first years of this century. 相似文献
140.
The interaction of drugs with DNA has been searched thoroughly giving rise to an endless number of findings of undoubted importance, such as a prompt alert to harmful substances, ability to explain most of the biological mechanisms, or provision of important clues in targeted development of novel chemotherapeutics. The existence of some drugs that induce oxidative damage is an increasing point of concern as they can cause cellular death, aging, and are closely related to the development of many diseases. Because of a direct correlation between the response, strength/ nature of the interaction and the pharmaceutical action of DNA‐targeted drugs, the electrochemical analysis is based on the signals of DNA before and after the interaction with the DNA‐targeted drug. Nowadays, nanoscale materials are used extensively for offering fascinating characteristics that can be used in designing new strategies for drug‐DNA interaction detection. This work presents a review of nanomaterials (NMs) for the study of drug‐nucleic acid interaction. We summarize types of drug‐DNA interactions, electroanalytical techniques for evidencing these interactions and quantification of drug and/or DNA monitoring. 相似文献