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151.
Peter ?ernoch Petr Štěpánek Miroslav Šlouf Manfred Stamm 《European Polymer Journal》2007,43(4):1144-1153
A systematic study of formation of surface patterns in block copolymer thin layers after their exposure to solvent vapors was performed. The studied effect involves layers of thickness approximately equal to the ordering size of polymers - about 45 nm. Experiments were performed on three styrene - methacrylate derivative block copolymers, synthesized by living anionic polymerization: poly(4-octylstyrene)-block-poly(butyl methacrylate), poly(4-fluorostyrene)-block-poly(butyl methacrylate) and poly(p-octylstyrene)-block-poly(methyl methacrylate). The polymers were exposed to vapors of chloroform, 1,4-dioxane, hexane, acetone and tetrahydrofuran. 相似文献
152.
Lambert C Nöll G Zabel M Hampel F Schmälzlin E Bräuchle C Meerholz K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(17):4232-4239
Two highly substituted azulene derivatives were synthesised by Pd-mediated dimerisation from the corresponding tolan species. One azulene derivative (2) has donor functionalities (dianisylaminophenyl and dianisylamino) in the 1-, 2-, 3- and 6-positions, while the other (1) has donors (dianisylaminophenyl) in the 2- and 6-positions and acceptors (nitrophenyl) in the 1- and 3-positions. Each azulene derivative shows strong bond length alternation in the solid state, determined by X-ray crystal analysis, and an intense CT band around 450-500 nm in its UV/Vis spectrum. The first-order hyperpolarisability of 1 and of 2 was measured by hyper-Rayleigh scattering and is about that of disperse red DR1. Both azulene derivatives show multiple oxidation processes. The intramolecular adiabatic ET behaviour of the mixed valence radical cations of 1 and of 2 was investigated by UV/Vis/NIR spectroelectrochemistry. The intervalence-CT band of 1(+) could be analysed by the Generalised Mulliken-Hush theory, which yields an electronic coupling V=1140 cm(-1) for the optically induced adiabatic hole transfer. 相似文献
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155.
Summary A procedure for the analysis of individual asbestos fibres in the submicrometre diameter range, based on the ratio method of thin film analysis, is presented. The reliability of this method has been tested in a study of identification of asbestos fibres. The systematic and statistical errors were investigated.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
Beitrag zur quantitativen Röntgenmikroanalyse einzelner Submikrometerteilchen: Asbestfasern
Zusammenfassung Es wurde versucht, eine Quantifizierungsmethode analog der Verhältnismethode zur Analyse dünner Schichten für die Analyse von Asbestfasern mit Durchmessern im Submikrometerbereich zu entwickeln. Die Zuverlässigkeit der Methode wurde mit einem Anwendungsbeispiel überprüft, und alle systematischen und statistischen Fehler wurden dargelegt.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
156.
Hartmut Schenkluhn Roland Berger Bernd Pittel Manfred Zähres 《Transition Metal Chemistry》1981,6(5):277-287
Summary The property-specific ligand control of 28 ligands on the decomposition temperatures in solution, measured by d.t.a. of a four-coordinate nickel(II)-complex is reported. A quantitative separation of electronic and steric effects by a multilinear regression analysis (75% electronic and 25% steric influence for the chosen ligands) is presented. The controlling effect of the selectivity on the decomposition (fraction of the C-C-linked product) (25 P-ligands) leads to an electronic: steric ratio of the property-specific ligand control of 5545 for the chosen ligands. An increase in the relative acceptor character of the P-ligands relatively destabilizes the complexes and thereby favours formation of a C-C-bond. An increase in steric hindrance also favours C-C-bond formation. A method for revising the steric parameter of P-ligands is presented and is used to correct the -value of (PhCH2)3P is corrected to 135°. SCCC-MO-calculations for testing the chemical reasoning of the separated electronic and steric ligand property control are shown. 相似文献
157.
Manfred Schreiner Peter Ettmayer Richard Kieffer 《Monatshefte für Chemie / Chemical Monthly》1982,113(8-9):869-876
Molybdenum-tungsten-carbonitrides can be prepared by reacting prealloyed powders of Mo and W with carbon in the presence of nitrogen or ammonia. Single phase carbonitrides (Mo, W) (C, N) with the WC-type structure can be obtained. The nitrogen content of these carbonitrides increases with increasing molybdenum content. Flowing ammonia has a decarburizing effect, which has to be counterbalanced by an addition of a carbonaceous gas such as methane. Nitrogen instead of ammonia is equally effective and gives carbonitrides which have a nitrogen content only insignificantly lower than the carbonitrides obtained in flowing ammonia. The lattice parameters of the carbonitrides are found to be slightly smaller than the lattice parameters of the corresponding carbides. 相似文献
158.
The synthesis and the photochemical behaviour of 4 new 2H-1.4-oxazines and 3 new spiro-2H-1.4-oxazines is described. 相似文献
159.
160.
The [4 + 2] cycloaddition stereoselectivity of dienamines 1–4 with dimethyl fumarate and fumaronitrile has been investigated, and functionalised decalins 21–40 have been prepared by elimination of Me2NH from cycloadducts 7–11 and 15–20 ; in the context of the synthesis of drimane sesquiterpenes, the reduction of dienediesters 29 and 30 is also described. 相似文献