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111.
Sensitized photo-oxidation of methylcyclohexane as a thin film on seawater by irradiation with natural sunlight 总被引:1,自引:0,他引:1
Methylcyclohexane dissolved in and forming a thin film on purified seawater with traces of anthraquinone added as triplet sensitizer was exposed to natural sunlight in a quartz flask. The water was circulated through a glass cartridge filled with Amberlite XAD-2 for the concentration of reaction products which were identified by GC/MS after elution and silica gel chromatography. They included isomeric methylcyclohexanols as the principal components, primary hydroperoxides, a tentatively identified secondary peroxide, methylcyclohexanones, and acyclic ketones. Mass spectra and mechanisms are discussed as well as possible biological consequences of the formation of these compounds. 相似文献
112.
Summary The azo dyes eriochrome black T, eriochrome blueblack R and eriochrome blueblack B and their complexes with cobalt, manganese and magnesium show adsorption enrichment on carbon paste electrodes, dependent on the composition of the electrode filling. This effect may be used for the determination of cobalt and manganese by a.c. voltammetry in the 10–7 to 10–6 M range. Standard deviation has been found to be ± 3.2 and ± 3.5%, respectively.
Adsorptive Anreicherung einiger Komplexe von Azofarbstoffen an einer Kohlepasteelektrode. Anwendung zur Bestimmung geringer Konzentrationen von Kobalt und Mangan
Zusammenfassung Die Azofarbstoffe Eriochromschwarz T, Eriochromblauschwarz B und Eriochromblauschwarz R sowie ihre Komplexe mit Kobalt, Mangan und Magnesium werden adsorptiv an Kohlepasteelektroden angereichert. Die Anreicherung ist von der Zusammensetzung der Elektrodenfüllung abhängig. Anwendungen zur wechselstromvoltammetrischen Bestimmung von Kobalt und Mangan im 10–7 bis 10–6 M Bereich werden beschrieben. Die Standardabweichung liegt bei ± 3,2 bzw. ± 3,5%.
Die Untersuchungen wurden in dankenswerter Weise durch Mittel der Deutschen Forschungsgemeinschaft und des Verbandes der chemischen Industrie unterstützt. 相似文献
113.
114.
Saalfrank RW Glaser H Demleitner B Hampel F Chowdhry MM Schünemann V Trautwein AX Vaughan GB Yeh R Davis AV Raymond KN 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(2):493-497
In a one-pot reaction, the tetranuclear iron chelate complex [Fe4(L4)4] 6 was generated from benzene-1,3,5-tricarboxylic acid trichloride (4), bis-tert-butyl malonate (5a), methyllithium, and iron(II) dichloride under aerobic conditions. Alternatively, hexanuclear iron chelate complex [Fe(L5)6] 7 was formed starting from bis-para-tolyl malonate (5b) by employing identical reaction conditions to those applied for the synthesis of 6. The clusters 6 and 7 are present as racemic mixtures of homoconfigurational (delta,delta,delta,delta)/(lambda,lambda,lambda,lambda)-fac or (delta,delta,delta,delta,delta,delta)/(lambda,lambda,lambda,lambda,lambda,lambda)-fac stereoisomers. The structures of 6 and 7 were unequivocally resolved by single-crystal X-ray analyses. The all-iron(III) character of 6 and 7 was determined by M?ssbauer spectroscopy. 相似文献
115.
The two new compounds [Fe(tren)]FeSbS4 ( 1 ) (tren = tris(2‐aminoethyl)amine) and [Fe(dien)2]Fe2Sb4S10 ( 2 ) (dien = diethylendiamine) were prepared under solvothermal conditions and represent the first thioantimonates(III) with iron cations integrated into the anionic network. In both compounds Fe3+ is part of a [2FeIII‐2S] cluster which is often found in ferredoxines. In addition, Fe2+ ions are present which are surrounded by the organic ligands. In ( 1 ) the Fe2+ ion is also part of the thioantimonate(III) network whereas in ( 2 ) the Fe2+ ion is isolated. In both compounds the primary SbS3 units are interconnected into one‐dimensional chains. The mixed‐valent character of [Fe(tren)]FeSbS4 was unambiguously determined with Mössbauer spectroscopy. Both compounds exhibit paramagnetic behaviour and for ( 1 ) a deviation from linearity is observed due to a strong zero‐field splitting. Both compounds decompose in one single step. 相似文献
116.
Markus Neuenschwander Peter Bigler Klaus Christen Rudolf Iseli Rolf Kyburz Hansueli Mühle 《Helvetica chimica acta》1978,61(6):2047-2058
Chloroacylation and bromoacylation of carbonyl compounds: A forgotten carbonyl reaction. I. Scope of the reaction Aliphatic, α,β-unsaturated and aromatic aldehydes as well as aliphatic ketones react with acyl halides to (α-haloalkyl)esters. These bifunctional derivates contain two leaving groups of different reactivity. The scope of this scarcely of this scarcely known carbonyl reaction is discussed. 相似文献
117.
Rolf Trautner 《manuscripta mathematica》1975,15(1):45-63
Let H x a regular Hausdorff method and P(w)=∑ ak wk a power series with positive radius of convergence. A theorem of Okada states that P(w) is summable (H x ) for w in a certain starshaped region G(H x ,P). We call G=G(H x ,P) the exact region of summability for P if summability cannot hold for any w \( \in \bar G\) Okada's theorem is said to be sharp for Hx if G(Hx,P) is the exact region of summability for any P. Three items are treated: 1. Criteria for Okada's theorem to be sharp are given in terms of the distribution function X (t) and the Mellin transform \(D(z) = \int\limits_0^1 {t^z d\chi (t)} \) . 2. When is Okada's theorem sharp for product methods? 3. Special classes of functions P(w) are indicated such that G(Hx, P) is the exact region of summability for any Hx. We use the notations of “Hausdorff-Summability of Power Series I” referred as “I”. 相似文献
118.
In this note we give examples of one-dimensional noetherian local integral domains with the property that the number of generators of the square of the maximal ideal is less than the embedding dimension. On the other hand we show that if \((R,m)\) is a local one-dimensional Cohen-Macaulay ring, then \((m^n )\) for all n such that μ \((m^n )\) < m(R). Here μ denotes the minimal number of generators of an ideal and m(R) the multiplicity of R. A similar statement was conjectured by D. Sally in [5], Our main result 2.1 generalizes Prop. 2.6. in [6]. 相似文献
119.
In this paper we are concerned with the summability of the geometric series
by matrix methods. We prove the following theorem: Suppose Mo:={z:|z|<1}, M1, M2, is a collection of countably many Lebesgue measureable, disjoint sets. For k=1,2, let fk be a prescribed function, analytic on
. Then there exists a triangular matrix
, such that the V-transform {n(z)} of the geometric series has the following properties: {n(z)} converges compactly to
on Mo; for k=1,2, there are sets Bk, such that
has Lebesgue-measure zero and n(z)fk(z) for zBk; if
there is a set B*, such that B*M* has Lebesgue-measure zero and {n(z)} diverges for zB*. 相似文献
120.
Iwan Jerjen Vincent Revol Andreas J. Brunner Philipp Schuetz Christian Kottler Rolf Kaufmann Thomas Luethi Giovanni Nicoletti Claus Urban Urs Sennhauser 《Polymer Testing》2013
The processing of thermoplastics can induce a wide range of defects such as stress whitening, cavitation and porosity, which can adversely affect the reliability of the final products. Hence, fast and effective non-destructive detection methods for such defects are highly important for quality assurance on production lines. In this paper, X-ray dark field imaging is presented as a new non-destructive testing method that allows the visualization of stress whitening or cavitation efficiently. The performance of the method is demonstrated for the case of an injection-moulded polyvinylidene fluoride part that exhibits stress whitening. Whereas the stress whitening could not be detected by conventional X-ray imaging, it was localized by an X-ray dark field image acquired within a few minutes. Once the precise location of the stress whitening was known, it was possible to verify the result by local micro X-ray computed tomography and by a micro section image. 相似文献