Massenspectroskopie von Naturstoffen. XV. Vergleichende Kationen-Anionen-Massenspektroskopie von Azidogibberellinen

Mass Spectrometry of Natural Products. XV. Comparative Positive-Negative Ion Mass Spectrometry of Azidogibberellins The fragmentation behaviour of 1-azido-3-hydroxy-gibberellin derivatives has been studied by means of positive and negative ion mass spectrometry, high resolution and metastable transitions. The results obtained allow a mass spectrometric distinction to be made between epimers with different stereochemistry of the ring A substituents.     

Ethernet für die Feldebene

Firmen&;ProdukteSiemens A&;D, I&;S

Ethernet für die Feldebene     

Selective optical detection of aromatic vapors

A sensitive layer system of amorphous Teflon AF on silver has been coated on a glass substrate. With a monochromatic light source the reflectivity of the layer system as a function of the angle of incidence exhibits the surface-plasmon resonance as well as a set of leaky-mode resonances. These optical resonance phenomena are sensitive to small refractive-index changes that may be induced by diffusion of particles into the Teflon AF layer. On the basis of this effect, the aromatic vapors benzene; toluene; and o-, p-, and m-xylene have been investigated with different vapor concentrations. By selection of a distinct angle at a particular resonance, dynamic measurements can be performed. Assuming a diffusion process in accordance with Fick's law, the diffusion profile can be calculated as a function of time. As described by the Lorentz-Lorenz relation a refractive-index profile is induced that consequently interacts with the electromagnetic fields of the optical modes. With the function of the diffusion-induced refractive-index profile the shift of the resonance lines can be calculated from the measured reflectivity change as a function of time. The characteristic diffusion coefficients of the particular vapor allow for a distinction between the different types of aromate, even between the different xylenes.     

Towards a cognitive foundation for knowledge representation

Abstract. Knowledge engineering, knowledge management and conceptual modelling are concerned with representing knowledge of business and organizational domains. These research areas use ontologies for knowledge representation. Ontologies are understood either in the philosophical sense as firm metaphysical commitments or in the looser sense of dictionaries or taxonomies.
This paper critically examines the understanding and use of ontologies and knowledge representation languages in information systems (IS) research and application. As ontologies are intended to be conceptualizations of a perceived reality, they should reflect the empirically observed reality. This motivates proposing psychology of language as a reference discipline for knowledge engineering and knowledge management. Natural language is argued to reflect the cognitive concepts we use to think about and perceive the world around us. These cognitive concepts are the relevant terms with which to structure and represent knowledge about the world.
Psychology of language can provide empirical justification for a particular set of concepts to represent knowledge. This paper draws on psycho-linguistic research to develop a proposal for a system of cognitive structures. This is argued to provide the relevant concepts on which to found knowledge representation schemata for knowledge engineering, knowledge management and conceptual modelling.     

Non-destructive and non-invasive observation of friction and wear of human joints and of fracture initiation by acoustic emission

Quality control in orthopaedic diagnostics according to DIN EN ISO 9000ff requires methods of non-destructive process control, which do not harm the patient by radiation or by invasive examinations. To obtain an improvement in health economy, quality-controlled and non-destructive measurements have to be introduced into the diagnostics and therapy of human joints and bones. A non-invasive evaluation of the state of wear of human joints and of the cracking tendency of bones is, as of today's point of knowledge, not established. The analysis of acoustic emission signals allows the prediction of bone rupture far below the fracture load. The evaluation of dry and wet bone samples revealed that it is possible to conclude from crack initiation to the bone strength and thus to predict the probability of bone rupture.     

Integration of Product Design and Assembly Planning in the Digital Factory

As assembly process planning fulfils the main function of connecting product design to production simulation and thus, the production system itself, a feasible software solution is needed to support this process. Thus, a novel concept is presented that aims at improving the integration of digital product design and assembly planning by introducing a consistent data structuring. This approach helps to reduce redundant tasks and supports the continuous data exchange. It is based on the use of assembly features, i.e. pre-defined geometry elements that contain additional technological information.The prototypical implementation of the concept focuses on the use of commercially available software tools, expanding them with additional functionality for the application of assembly features. The feature-based concept has been tested with a scenario from the automotive supplier industry. For the considered assembly, a comparison between the conventional and the feature-based planning approach is presented in the paper. It points out that the major advantages of the developed concept can be seen in an improved data consistency as well as a higher level of efficiency within the planning activities.     

结构工程师和建筑师

在工业革命的进程中，人们逐渐能够计算和生产几何形状与强度符合要求的铁（后来称为钢）结构建筑。于是统管全程的建筑大师和工作突然被划分成两个职业，建筑师和结构工程师。1748年伽利略为罗马圣彼得教堂的圆屋顶绘制了图样报告，这标志着结构工程学的诞生。     

Identification of the Sex Pheromone of the Currant Shoot Borer Lampronia capitella

Under an artificial light:dark cycle, females of Lampronia capitella were observed calling, with extended terminal abdominal segments, during the first 2 hr of the photoperiod. Extracts of terminal abdominal segments from females elicited large electroantennographic responses from male antennae. Gas chromatography with electroantennographic detection revealed three active peaks. Based on comparison of retention times and mass spectra of synthetic standards, these compounds were identified as (Z,Z)-9,11-tetradecadienol and the corresponding acetate and aldehyde. The electroantennographic activity of the four geometric isomers of all three compounds was investigated, and the respective (Z,Z)-isomer was found to be the most active in all cases. Aldehydes generally elicited larger antennal responses than alcohols, whereas acetates were the least active compounds. A subtractive trapping assay in the field, based on a 13:26:100 micrograms mixture of (Z,Z)-9,11-tetradecadienal, (Z,Z)-9,11-tetradecadienyl acetate, and (Z,Z)-9,11-tetradecadienol confirmed that all three compounds are pheromone components. Subtraction of (Z,Z)-9,11-tetradecadienol from the blend completely eliminated its attractiveness, whereas the other two-component blends showed reduced activity. This is the first pheromone identification from the monotrysian superfamily Incurvarioidea, confirming that the common pheromones among ditrysian moths (long-chain fatty acid derivatives comprising alcohols, acetates, and aldehydes with one or more double bonds) is not an autapomorphy of Ditrysia, but a synapomorphy of the more advanced heteroneuran lineages.