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1.
Palladium and molybdenum polycrystalline layers (clusters) have been deposited in a stainless steel UHV system onto a layer of alumina (Al2O3). This layer has been prepared by high temperature oxidation of an aluminium layer. The interaction of this system with nitrogen has been investigated at room temperature by an FEM technique. Under these conditions nitrogen spillover from molybdenum to palladium has been observed. 相似文献
2.
Steven D. Bull Simon W. Epstein Nadeam Mujtaba Edward D. Savory Juan A. Tamayo 《Tetrahedron》2006,62(33):7911-7925
Enolates of (S)-N,N′-bis-(p-methoxybenzyl)-3-iso-propylpiperazine-2,5-dione exhibit high levels of enantiodiscrimination in alkylations with (RS)-1-aryl-1-bromoethanes and (RS)-2-bromoesters, affording substituted diketopiperazines containing two new stereogenic centres in high de. Deprotection and hydrolysis of the resultant substituted diketopiperazines provides a route to the asymmetric synthesis of homochiral methyl 2-amino-3-aryl-butanoates and 3-methyl-aspartates in high de and ee. 相似文献
3.
V. Balek T. Mitsuhashi I.M. Bountseva H. Haneda Z. Malek J. Šubrt 《Journal of Sol-Gel Science and Technology》2003,26(1-3):185-189
The diffusion structural analysis (DSA) was used to characterize microstructure changes of hydrous titania gel films under in situ conditions of heating. TG and DTA were used in order to elucidate the processes controlling the formation of anatase film during heating of hydrous titania gel film. The annealing of porosity and near surface structure defects of the dehydrated titania films was indicated by DSA in the temperature range 255–700°C as the decrease of radon release rate. It was demonstrated that the annealing was enhanced on heating in oxygen in comparison with heating in argon. The DSA experimental results were compared with model curves describing the radon diffusion mobility and the annealing of radon diffusion paths. 相似文献
4.
5.
Fe(II)--Fe(III) hydroxy-chloride, -sulphate and -carbonate were prepared by oxidation of a ferrous hydroxide precipitate in anion-containing aqueous solutions. The compounds are characterized by monitoring the redox potential Eh and the pH of stochiometric suspension vs time with the appropriate concentration ratios. X-ray diffraction allows us to characterize the crystal structure by distinguishing “green rust one” (GR1) from “green rust two” (GR2). Since green rusts (GRs) are of a pyroaurite-sjögrenite-like structure, i.e., consisting of intercalated foreign anions and water molecules in the interlayers between the brucite-like layers of Fe(OH)2, their chemical formulae can be determined from the Mössbauer spectra. Three quadrupole doublets are observed: D1 and D2 correspond to a ferrous state with isomershift IS of about 1.27 mm s-1 and quadrupole splittings QS of about 2.85 and 2.60 mm s-1, respectively, whereas D3 corresponds to a ferric state with IS and QS of about 0.4 mm s-1. The hyperfine parameters of these doublets are similar from one green rust to another but their intensity ratios vary considerably. Finally, Eh and pH equilibrium diagrams of the Fe species in the presence of chloride, sulphate and carbonate anions contained within the water solution are drawn and the thermodynamic conditions of existence and degrees of oxidation of green rusts are discussed. 相似文献
6.
Botjan Japelj Simon Re
nik Petra ebaek Branko Stanovnik Jurij Svete 《Journal of heterocyclic chemistry》2005,42(6):1167-1173
A series of alkyl l‐heteroaryl‐1H‐1,2,3‐triazole‐4‐carboxylates 6a‐u were synthesised in four steps from methyl (Z)‐2‐benzyloxycarbonylarmino‐3‐(dimethylamino)prop‐2‐enoate ( 1 ) and heterocyclic amines 2a‐s. Triazoles 6a‐o were tested against antimycobacterial activity. For the most active compound, n‐pentyl 1‐(6‐phenylpyridazin‐3‐yl)‐1H‐1,2,3‐triazole‐4‐carboxylate ( 6n ), minimum inhibitory concentration 3.13 μg/ml was determined. 相似文献
7.
Peter Šimon 《Journal of Thermal Analysis and Calorimetry》2006,83(3):521-522
This
issue of Journal of Thermal Analysis and Calorimetry contains selected papers
based on presentations in the field of thermal characteristics of advanced
polymer systems presented at the 8th International
Symposium on Polymers for Advanced Technologies (PAT 2005) held in Budapest,
September 2005.
Guest Editors 相似文献
8.
Simon R. Blackburn 《Journal of Combinatorial Theory, Series A》2006,113(7):1572-1581
The paper contains proofs of the following results. For all sufficiently large odd integers n, there exists a set of 2n−1 permutations that pairwise generate the symmetric group Sn. There is no set of 2n−1+1 permutations having this property. For all sufficiently large integers n with n≡2mod4, there exists a set of 2n−2 even permutations that pairwise generate the alternating group An. There is no set of 2n−2+1 permutations having this property. 相似文献
9.
Journal of Statistical Physics - Let V 0be a real-valued function on [0,∞) and V∈L 1([0,R]) for all R&;gt;0 so that H(V 0)=? $\frac{{d^2 }}{{dx^2 }}$ +V 0in L 2([0,∞))... 相似文献
10.