7,077 research outputs found
Design of dual functional adsorbent/catalyst system for the control of VOC's by using metal-loaded hydrophobic Y-zeolites
No full textTo design a good combined adsorbent/catalyst dual functional system for the control of the low concentration VOC, both adsorption and catalytic activity test over metal-loaded zeolite HY were carried out. Hydrophobic HY zeolite was selected as a good adsorbent candidate among the tested zeolite adsorbents and extended to the catalyst support material by adding various transition metals. The temperature programmed surface reaction (TPSR) of toluene and methylethylketone (MEK) suggested the silver as the best candidate among the tested transition metals. Temperature programmed reductions (TPR) and O-2-temperature programmed desorption (O-2-TPD) on Ag/HY catalysts were carried out to explain the nature of active centre of Ag catalyst for the toluene oxidation. Silver oxide species or partially oxidized metallic silver on to the surface of metallic silver phase was proposed as an active redox site during the oxidation reaction. (C) 2004 Elsevier B.V. All rights reserved
Effects of CO2 addition on the aromatization of propane over metal-loaded ZSM-5 catalysts
No full textThe catalytic reduction of CO2 accompanying the aromatization of propane is a new type of catalytic reaction for the utilization of CO2, CO2 is reduced into CO by hydrocarbon, and hydrocarbon (propane) is converted into more valuable products; This type of reaction is more economical than the hydrogenation of CO2, since propane is much cheaper than hydrogen, The combined conversion of propane and CO2 was investigated by using metal-loaded ZSM-5 catalysts, which were characterized by temperature-programmed desorption, X-ray diffraction, thermogravimetric analysis and BET analysis. Reduction of CO2 by propane resulted in higher conversion of CO2 and higher CO yield than that by hydrogen. The incorporation of metal ions, such as Zn2+ Cr3+, Fe3+ and Ni2+, into HZSM-5 enhanced the catalytic activity for CO2 reduction, The addition of CO2. was found to suppress the coke deposition during the aromatization of propane. Copyright (C) 2000 John Wiley & Sons, Ltd
Random field Ising model and community structure in complex networks
No full textWe propose a method to determine the community structure of a complex network. In this method the ground state problem of a ferromagnetic random field Ising model is considered on the network with the magnetic field B s=+∞, B t=-∞, and B i≠s,t =0 for a node pair s and t. The ground state problem is equivalent to the so-called maximum flow problem, which can be solved exactly numerically with the help of a combinatorial optimization algorithm. The community structure is then identified from the ground state Ising spin domains for all pairs of s and t. Our method provides a criterion for the existence of the community structure, and is applicable equally well to unweighted and weighted networks. We demonstrate the performance of the method by applying it to the Barabási-Albert network, Zachary karate club network, the scientific collaboration network, and the stock price correlation network. (Ising, Potts, etc.) Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200689.75.Hc Networks and genealogical trees, 89.65.-s Social and economic systems, 05.10.-a Computational methods in statistical physics and nonlinear dynamics, 05.50.+q Lattice theory and statistics,
Niemcza diorites and moznodiorites (Sudetes, SW Poland): a record of changing geotectonic setting at ca. 340 Ma
No full textGranites sensu lato in the Sudetes intruded in several episodes during the Variscan orogeny recording different stages of crust and mantle evolution. Correlating precise ages with geochemistry of the Variscan granites provides information on the evolution of these sources within the Variscan orogen. The Variscan intrusive rocks from the Niemcza Zone (Bohemian Massif, Sudetes, SW Poland) include undeformed dioritic to syenitic rocks and magmatically foliated granodiorites. In this study we analysed low SiO2 (48–53 wt.%) monzodioritic rocks from Przedborowa and Koźmice. The monzodiorites contain late-magmatic zircons with ages of 341.8 ± 1.9 Ma for Przedborowa and 335.6 ± 2.3 Ma for Koźmice, interpreted as emplacement ages of the dioritic magmas. Older Przedborowa rocks are lower in K, Mg, Rb and Ni than the Koźmice rocks and similar compositional trend is also observed in the Central Bohemian Plutonic Complex. The implication is that the mantle underlying the Niemcza Zone became more enriched from ca. 342 to ca. 336 Ma, probably following the collision of the Saxothuringian and Moldanubian/Lugian domains. The magmatism related to the collision occurred ca. 12 Ma later than that in the Central Bohemian Plutonic Complex, but was accompanied by a similar change in magma chemistry from high-K (Przedborowa) to shoshonitic (Koźmice, Kośmin enclaves) and probably to ultrapotassic (Wilków Wielki)
Comparison of (hexafluoroacetylacetonate) Cu(vinyltrimethylsilane) and (hexafluoroacetylacetonate) Cu(allyltrimethylsilane) for metalorganic chemical vapor deposition of copper
No full textFor the metalorganic chemical vapor deposition (MOCVD) of copper, (hfac)Cu(VTMS) (hfac = hexafluoroacetylacetonate, VTMS = vinyltrimethylsilane) and (hfac)Cu(ATMS) (ATMS = allyltrimethylsilane) were compared, and the effect of L ligand in (hfac)Cu-L was examined. It was found by H-1-NMR (nuclear magnetic resonance) that the thermal stability of (hfac)Cu(VTMS) was better than that of (hfac)Cu(ATMS) due to the relatively weak Cu-ATMS bond. From in situ Fourier transform infrared spectroscopy (FTIR) experiments, the formation of Cu(hfac)(2), the product of disproportion reaction of Cu(hfac), was observed in the gas phase and (hfac)Cu(ATMS) was found to be more reactive to form Cu(hfac)(2). The minimum temperature for the deposition of copper films from (hfac)Cu(ATMS) was as low as 60 degrees C, which was about 70 degrees C lower than from (hfac)Cu(VTMS). The grain size of the film deposited with (hfac)Cu(ATMS) was substantially larger than that with (hfac)Cu(VTMS), which showed that the chemical reactivity of the precursor had an influence on the microstructure along with the deposition temperature.X1129sciescopu
Growth rate and microstructure of copper thin films deposited with metal-organic chemical vapor deposition from hexafluoroacetylacetonate copper(I) allyltrimethylsilane
No full textMetal-organic chemical vapor deposition of copper using the copper(I) compound, (hfac)Cu(ATMS) (hfac = hexafluoroacetylacetonate, ATMS = allyltrimethylsilane) as a precursor, was carried out on TiN surface over a substrate temperature range of 60 similar to 275 degrees C. It was found that the deposition temperature could be substantially lower compared with (hfac)Cu(VTMS) (VTMS = vinyltrimethylsilane). In the substrate temperatures ranging from 60 to 90 degrees C, the Arrhenius plot showed a reaction-rate-limited regime with an activation energy of 15.0 kcal/mol. Above 90 degrees C, the deposition rate showed a feed-rate-limited regime with an activation energy of 0.1 kcal/mol. The copper films contained no detectable impurities by Auger electron spectroscopy and gave resistivities below 2.0 mu Omega cm in the temperature range of 125 similar to 170 degrees C. As substrate temperature increased, the small-grained, smooth and continuous film structure changed to large-grained and rough film structure that was poorly connected and resulted in high resistivities. The polycrystalline phases with a preferred orientation of (111) and loss of selectivity were observed over a wide range of substrate temperatures. (C) 1998 Elsevier Science S.A. All rights reserved.X1127sciescopu
구조체
No full textA structure, and more specifically a tube-shaped structure having an inner surface and two ends, wherein one or both ends are open and the inner surface is exposed through said one or both open ends, and a metal provide on the inner surface. Also, an electrode active material, such as lithium metal, on the metal included on the inner surface of the tube
G2 & G1 plants species of SW Colorado
No full textPresented at the 16th symposium held on September 27, 2019 in Grand Junction, Colorado.2019 G2 species of SW Colorado -- 2019 G1 species of SW Colorado
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