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261.
Juraj??ernákEmail author Fran?ois?Gérard Charles?Kappenstein Jozef?Chomi? 《Monatshefte für Chemie / Chemical Monthly》2004,135(9):1081-1088
Summary. Coordination compounds Zn(mal)(H2O)2 (ZMH) (mal=maleate anion (C2H2(CO2)22-)), Cu0.06Zn0.94(mal)(H2O)2 (ZCMH), Cu(mal)(H2O) (CMH), and physical mixtures of CMH and ZMH were used as precursors for calcination experiments in air at 500 and 1000°C lasting 18 hours. The obtained oxides were investigated by X-ray powder diffraction technique. Calcination at 500°C yielded pure zincite phase (ZnO), tenorite phase (CuO), or their mixtures. The calcination of the Zn-rich sample ZCMH at 1000°C lead to zincite phase displaying a slightly lower cell volume than the pure zincite phase obtained from Zn-only containing precursor (ZMH). These results suggest that the assumed solid solution CuxZn1–xO (x=0.01–0.02) exhibits a solubility limit lower than the copper content in the ZCMH precursor (6mol-%). On the other hand, the calcination of the Cu-rich samples at 1000°C, in the presence of Zn(II), yielded tenorite phase exhibiting cell parameters significantly different from those reported for the pure tenorite phase, due to the formation of Zn0.03Cu0.97O solid solutions. All these results are corroborated by intensity analysis of the diffraction peaks. 相似文献
262.
Juraj ernk Khalil A. Abboud 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):m167-m170
Partial reduction of the CuII ions in the aqueous system CuII–en–[Ni(CN)4]2? (1/1/1) (en is 1,2‐diaminoethane) yields a novel heterobimetallic mixed‐valence compound, poly[[aquabis(1,2‐diaminoethane)copper(II)] [hexa‐μ‐cyano‐tetracyanobis(1,2‐diaminoethane)tricopper(I,II)dinickel(II)] dihydrate], [Cu(C2H8N2)2(H2O)][Ni2Cu3(CN)10(C2H8N2)2]·2H2O or [Cu(en)2(H2O)][Cu(en)2Ni2Cu2(CN)10]·2H2O. The structure is formed by a negatively charged two‐dimensional array of the cyano complex [Cu(en)2Ni2Cu2(CN)10]n2n?, [Cu(en)2(H2O)]2+ complex cations and water molecules of crystallization. These last are involved in a complicated hydrogen‐bonding system. The cyano groups act as terminal, μ2‐bridging or μ3‐bridging ligands. 相似文献
263.
Werner Massa Miroslava Mal'arov Juraj ernk 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):m119-m121
The title compound, {(C8H20N)[CdFe(CN)6(C2H8N2)2]·4H2O}n, was isolated from the aqueous system Cd2+/ethylenediamine (en)/[Fe(CN)6]3− in the presence of [Et4N]Br. The crystal structure is dominated by a one‐dimensional motif, viz. a negatively charged 2,2‐CT (cis–trans) [–Cd(en)2—NC—Fe(CN)4—CN–]nn− chain. The Cd and Fe atoms of the anion and the N atom of the cation all lie on twofold axes. The ethyl groups of the cation are equally disordered over two orientations. The cationic building block of the chain consists of a CdII atom coordinated by two chelating en ligands, and the distorted octahedral coordination is completed by two bridging cyano ligands in cis positions. The anionic building block is an [Fe(CN)6]3− anion in which the FeIII atom is octahedrally coordinated by six cyano ligands; two of the cyano ligands, in trans positions, are bridging. The uncoordinated water molecules link neighbouring chains through O—H⋯N and N—H⋯O hydrogen bonds. 相似文献
264.
Lang K Kubát P Mosinger J Bujdák J Hof M Janda P Sýkora J Iyi N 《Physical chemistry chemical physics : PCCP》2008,10(30):4429-4434
The treatment of nano-ordered oriented films of layered double hydroxide (LDH) with dodecyl sulfate increased the interlayer distance from 0.4 to 1.96 nm, which allowed the intercalation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS). The re-stacking of separated layers and the rebuilding of crystals oriented parallel to the surface of quartz slides was confirmed by X-ray diffraction and atomic force microscopy. The hybrid films contained homogeneously distributed porphyrin molecules with preserved photophysical properties such as fluorescence, triplet state formation, and energy transfer, thus forming singlet oxygen. 相似文献
265.
The transport of reaction species in polyolefin particles affects both the polymerization and the degassing of the powder in the down‐stream processing. The morphology of particles – that is, the distribution of polymer and pore phases – predetermines their degassing behavior. We utilize gravimetric measurements to obtain the dynamics of degassing and to determine morphology characteristics of porous poly(propylene) particles. We found that Fick's diffusion model is not generally capable of fitting the shape of degassing curves of porous particles. Therefore we propose a particle model including two sizes of compact polymer granules and demonstrate that the degassing can be described by this model and that the model is capable of estimating fractions of large and small compact zones and the size of large compact zones.
266.
Horáková J Petr J Maier V Znaleziona J Stanová A Marák J Kaniansky D Sevcík J 《Journal of chromatography. A》2007,1155(2):193-198
An on-line preconcentration capillary electrophoresis (CE) technique, which combines a large volume sample stacking with a dynamic pH junction technique, is introduced in this paper. This dynamic pH junction with co-electroosmotic migration is formed between sodium borate pH 9.5 and sodium phosphate pH 2.5 with 150 mM sodium dodecylsulfate (SDS). A full capillary based injection allows determination of weak acidic compounds at ppb concentration levels (achieved LOD for benzoic acid was 11 nmol L(-1)). The proposed preconcentration method was compared with ITP/ITP (LOD 120 nmol L(-1)), ITP/CZE (LOD 740 nmol L(-1)) and a simple CZE method (LOD 23,330 nmol L(-1)). The analytical potential of this method was assessed with juice test samples. 相似文献
267.
Infante I Raab J Lyon JT Liang B Andrews L Gagliardi L 《The journal of physical chemistry. A》2007,111(47):11996-12000
The vibrational spectra of UBz and ThBz have been measured in solid argon. Complementary quantum chemical calculations have allowed the assignments of the vibrational spectra. According to the calculations, AcBz are stable molecules, as well as other species like BzAcBz and BzAc2Bz. Experimentally, there is no evidence for the sandwich compounds BzAcBz and BzAc2Bz due to the limitations in the reagent concentrations. 相似文献
268.
Capillary electrophoresis-mass spectrometry - a fast and reliable tool for the monitoring of milk adulteration 总被引:2,自引:0,他引:2
The development of a rapid, simple and accurate analytical method aimed at the detection and quantification of bovine milk in either ovine or caprine milk samples by means of CE-MS analyses of whey proteins with high-ionic strength and presence of acidic running buffer is described. The high-ionic strength buffer was used in order to minimize the problems with the adsorption of the proteins onto the fused-silica capillary wall. The acidic running electrolyte, pH 1.9, was used to support the production of positive ions in electrospray. Highly linear dependences of the ratio of the sum of non-bovine beta-lactoglobulins (ovine or caprine) to the total beta-lactoglobulins in milk mixture (bovine plus ovine or bovine plus caprine) vs. the volume percentage of added bovine milk in ovine (or caprine) milk were obtained. This technique allowed the fast and reliable evaluation of milk adulteration. The amount of bovine milk added into the "non-bovine" ones can be well within the concentration range of 5-95%. 相似文献
269.
Helena Bruncková Ľubomír Medvecký Pavol Hvizdoš Juraj Ďurišin 《Surface and interface analysis : SIA》2015,47(11):1063-1071
Perovskite (K, Na)NbO3 (KNN) thin films (~100 nm) were prepared by sol–gel/spin coating process on Pt/SiO2/Si substrates and annealed at 650 °C. The structural properties of KNN films were confirmed by X‐ray diffraction analysis (XRD), Raman spectroscopy and scanning electron, transmission electron and atomic force microscopy (SEM, TEM and AFM) analysis. Pure perovskite phase of K0.65Na0.35NbO3 in nonstoichiometric composition with monoclinic symmetry in film was revealed. Uniform homogeneous microstructure of KNN film with the roughness (~6.9 nm) contained spherical particles (~50–90 nm). Nanoindentation technique was used to characterize the mechanical properties of KNN films. Elastic modulus and hardness of Pt, SiO2 and KNN thin films were calculated from their composite values of KNN/Pt/SiO2/Si film/substrate system. The modulus and hardness of KNN film (71 and 4.5 GPa) were lower in comparison with SiO2 (100 and 7.5 GPa). Pt film (~30 nm) did not influence the composite modulus, but had effect on hardness of KNN film. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
270.
L’ubomír Vančo Magdaléna Kadlečíková Juraj Breza Pavol Michniak Michal Čeppan Milena Reháková Eva Belányiová Beata Butvinová 《Chemical Papers》2015,69(4):518-526
Raman spectroscopy and surface enhanced Raman spectroscopy were used to examine 14 blue inks obtained from commercially available stationery. Standard colouring agents in the inks: β-phase of phtalocyanine blue PB15 and some homologues of the methyl violet class, were identified. Surface enhanced Raman spectra were recorded on a firm heterostructure of silver/nanocrystalline diamond/silicon constituting an active substrate providing the possibility to write directly on the surface. Based on the differences in traditional and surface enhanced Raman spectra, two inks were identified unambiguously, the remaining inks were categorised into three groups exhibiting common spectral features. Despite their similarity, surface enhanced Raman spectra exhibited soft variations enabling discrimination of the inks, thus proving the usefulness of the method. 相似文献