Über verallgemeinerte Momente additiver Funktionen

In this paper we give characterizations of additive functionsf, for which $$\mathop {\lim \sup }\limits_{x \to \infty } x^{ - 1} \sum\limits_{n \leqslant x} {\varphi (|f(n)|)}$$ is bounded, where φ: ?⁺ → ?⁺ is monotone and or $$\begin{array}{*{20}c} {\varphi (x) = c^x } & {(x \in \mathbb{R}).} \\ \end{array}$$ A typical example is φ (x)=x ^a (a>0) forx≥0.     

Use of solid-phase microextraction-capillary-gas chromatography (SPME-CGC) for the varietal characterization of wines by means of chemometrical methods

The extraction of wine aroma compounds was studied by direct-SPME (DI/SPME), headspace-SPME (HS/SPME) and multiple-headspace-extraction-SPME (MHE/SPME). The aromagrams obtained by HS/SPME-CGC were evaluated with chemometrical methods for the varietal classification of wines. Received: 25 July 1997 / Revised: 24 September 1997 / Accepted: 7 October 1997     

Untersuchungen an Alkylmetallalkoxiden der Elemente Aluminium,Gallium und Indium. III. Eigenschaften und Schwingungsspektren von Dialkylgallium- und Indiumalkoxiden

Studies on Alkyl Metal Alkoxides of Aluminium, Gallium, and Indium. III. Properties and Vibrational Spectra of Dialkylgallium- and Indium Alkoxides The preparation and the properties of dialkyl metal alkoxides R₂MOR′ (with R = CH₃, CD₃, C₂H₅; R′ = CH₃, CD₃ and M = Ga, In) are described. The vibrational data (IR and Raman) of the trimeric methyl derivatives point to puckered six-membered M₃O₃-ring systems.     

Phenazine, 3. Mitt.: N-(o-Aminophenyl)-benzo[a]phenazin-5-amin, das vermeintliche “Dihydronaphthodiphenazin”Kehrmanns, und seine Derivate

The dihydronaphthodiphenazine ofKehrmann, which is according toBadger andPettit reported to be 14-o-aminophenyl-13,14-dihydro-5,8,13,14-tetraaza-6,7-benzopentaphene, is N-(o-aminophenyl)-benzo[a]phenazin-5-amine. This was proved by chemical and spectroscopic investigations. The structures of the derivatives prepared byBadger andPettit are also corrected and the acetylation processes are cleared up.     

The effect of the ammonium paratungstate source on the tungsten crystallite size

In an investigation into the effects of CaCl₂ on the sulfation of limestones in a laboratory furnace simulating fluidized-bed coal combustion conditions, small additions of CaCl₂ (<1 mole%) to the limestone prior to calcination were found to increase the extent of sulfation by changing the limestone pore structure. These changes were effected by trace amounts of liquid in the system in a synthetic SO₂/O₂ flue gas at 850°C. At much higher concentrations of CaCl₂, large amounts of a liquid phase are produced, containing a substantial quantity of dissolved CaO and leading to greatly enhanced sulfation when exposed to SO₂/O₂. The use of CaCl₂ additive in fluidized-bed combustion would reduce the quantity of limestones required to meet air pollution standards for SO₂ and also reduce the quantity of solid waste generated.     

Über die bei hohen Ansäuerungsgraden auftretenden Polymolybdat-Typen,insbesondere zur Frage der „Dekamolybdate”︁ und „Phase C”︁-Polymolybdate

On the Polymolybdate Types Occurring at High Degrees of Acidification, with Particular Reference to the “Decamolybdates” and “Phase C” Polymolybdates It is shown that in the range of high acidification (> 1.6H⁺/MoO₄^2?) of aqueous molybdate solutions only two types of solid polymolybdates occur, namely the 36-molybdate and the “decamolybdate” types. These types can be most conveniently identified by their Raman spectra and also by some other characteristics. All the other polymolybdate types proposed in the literature for this range of acidification (“hexamolybdates”, “octamolybdates”, “dodecamolybdates”, “16-molybdates”, a 19-molybdate, the large group of polymolybdates characterized by a wide range of b in the general formula M₂O · bMoO₃ · cH₂O, “phase C” polymolybdates, a “hexagonal hydrate of molybdenum trioxide”, a “reactive molybdic acid”, “NH₃(MoO₃)₃”, and others) can be assigned to one of these two types. The most important reason for the erroneous assignments in the literature is the isomorphous exchange of varying quantities of the alkali or alkaline earth metal cations by H₃O⁺ in the crystal structure, occurring in the highly acidic solutions, particularly with the small cations. This cannot be recognized by the presently available methods of investigation and, hence, leads to the creation of new polymolybdate types. Another reason causing some of the confusion is the assignment of virtually identical X-ray diffraction data to two different types of lattices, a hexagonal and cubic lattice.     

Diverse redox-active molecules bearing O-, S-, or Se-terminated tethers for attachment to silicon in studies of molecular information storage

A molecular approach to information storage employs redox-active molecules tethered to an electroactive surface. Attachment of the molecules to electroactive surfaces requires control over the nature of the tether (linker and surface attachment group). We have synthesized a collection of redox-active molecules bearing different linkers and surface anchor groups in free or protected form (hydroxy, mercapto, S-acetylthio, and Se-acetylseleno) for attachment to surfaces such as silicon, germanium, and gold. The molecules exhibit a number of cationic oxidation states, including one (ferrocene), two [zinc(II)porphyrin], three [cobalt(II)porphyrin], or four (lanthanide triple-decker sandwich compound). Electrochemical studies of monolayers of a variety of the redox-active molecules attached to Si(100) electrodes indicate that molecules exhibit a regular mode of attachment (via a Si-X bond, X = O, S, or Se), relatively homogeneous surface organization, and robust reversible electrochemical behavior. The acetyl protecting group undergoes cleavage during the surface deposition process, enabling attachment to silicon via thio or seleno groups without handling free thiols or selenols.