Auf dem Weg zu idealen Programmierwerkzeugen – Bestandsaufnahme und Ausblick

Zusammenfassung  Angeregt durch Robert W. Floyds Turing-Award-Lecture ,,The Paradigms of Programming“ von 1979 [6] und motiviert durch die Unzufriedenheit des Praktikers mit dem Stand der Softwaretechnik aus vielen Industrieprojekten, versucht dieser Beitrag eine Bestandsaufnahme der Programmiertechnik und identifiziert die Defizite aus Sicht der Grundprinzipien des Konstruktionsprozesses. Mit der Objektorientierung sind, besonders in den letzten Jahren, viele neue Programmiersprachen entstanden, die sowohl Wert auf schnelle Entwicklungszyklen als auch auf Erweiterbarkeit legen. Die heute haupts?chlich verwendeten Sprachen und Umgebungen sind von diesen Zielen weit entfernt. Das Entwickeln von Software ist zum einen zu kompliziert und zum anderen schmerzt die ,,semantische Lücke“ zwischen den ausdrückbaren und den erforderlichen Konzepten. Neue, viel versprechende Programmiersprachen, die sich durchweg auf Metaprogrammierung stützen, um die erforderliche semantische Erweiterbarkeit der Sprachen zu erreichen, deuten die Richtung zukünftiger Entwicklungen an.     

Ziele und Methoden der elektrochemischen Verfahrens- und Reaktionstechnik

Objectives and methods of electrochemical process and reaction engineering . Electrolysis processes are distinguished from ?normal”? chemical processes in several respects: (1) The electrical energy consumed is expensive and assumed the role of an expensive raw material. (2) Mass transfer in electrolytes is sluggish and limits space time yield to relative low values. (3) The rate of reaction is dictated by the applied electrode potential and this determines the cell voltage and energy efficiency of electrolysis processes. Effective electrocatalysts diminish energy consumption per unit mass of product. (4) The relatively poor electrical conductivity of electrolytes leads to construction of special closely spaced cells with narrow cell gaps. It is important to select the operation conditions of, e. g. organo-electrosyntheses to minimise the efforts involved in isolation and purification of the product.     

Synthesis and X-ray crystal structure of a bis-cyclometalated phosphorescent red-emitting iridium(III) complex

The synthesis of the bis-cyclometalated complex [{Ir(μ-Cl)(ccpz)₂}₂] (1, cppz = 1-chloro-4-(4-chlorophenyl)-phthalazine) from hydrated iridium(III) chloride and the ligand ccpz in refluxing ethoxyethanol is described. Compound 1 was characterized by spectroscopic means and the crystal structure was determined by X-ray crystallography. The absorption and emission spectra exhibit the new compound as a red-emitting phosphorescent complex.     

Die nutzung gentechnischer methoden zur produktion wertvoller proteine in mikroorganismen

The genetic make-up of living systems especially of isolated cells can be altered by a variety of methods including chemical or light-induced mutation. More modern procedures are the in vitro recombination of nucleic acids and the cell-cell fusion. The new methods are especially useful to reprogram microorganisms to produce valuable proteins or other natural products in excess quantties. In the following we will elucidate the importance of the new techniques by describing the bacterial production of glucose dehydrogenase, of the proteinase inhibitor stefin A and by outlining the methods and promisses of substractive cloning. Although the economic value of genetic engineering techniques still awaits justification, the importance of the methodology for basic biological research is well documented.     

Diamondoid Phosphines – Selective Phosphorylation of Nanodiamonds[1]

The diamondoids (nanodiamonds) diamantane and triamantane were selectively converted into diorganophosphinic acid chlorides by reacting them with phosphorus trichloride under Friedel–Crafts‐like conditions. The di‐diamondoid phosphinic acid chlorides were subsequently reduced with trichlorosilane to give the hitherto unknown corresponding di‐diamondoid phosphines. These diamondoid phosphinic acid chlorides and phosphines are of great utility as starting materials in organo‐element and coordination chemistry due to their extraordinary rigidity and steric bulk.     

Adaptive exponential stabilization for a class of nonlinear retarded processes

This paper considers the problem of adaptive exponential stabilization for a class of single-input single-output nonlinear retarded processes. The class includes certain linear retarded systems which are subject to sector-bounded actuator and sensor nonlinearities. It is shown that there is a wide range of high-gain adaptive compensators which achieve exponential stability for the class of processes under consideration. This work was supported by SERC under Grant No. GR/D/45710.     

Fibre reinforced glasses

A new method of preparing fibre reinforced glasses is put forward, which is based on further developments of the known slurry method and the sol-gel technique. This method combines the advantages of the two procedures. The prepregs are hot-pressed and the influence of preparation parameters on the bending strength are investigated. The pressure, temperature, time of pressing, granulation of the glass powder, the type of sol-gel solution and the gas atmosphere during the hot-pressing were all studied.     

Freestanding silicon quantum dots: origin of red and blue luminescence

In this paper, we studied the behavior of silicon quantum dots (Si-QDs) after etching and surface oxidation by means of photoluminescence (PL) measurements, Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance spectroscopy (EPR). We observed that etching of red luminescing Si-QDs with HF acid drastically reduces the concentration of defects and significantly enhances their PL intensity together with a small shift in the emission spectrum. Additionally, we observed the emergence of blue luminescence from Si-QDs during the re-oxidation of freshly etched particles. Our results indicate that the red emission is related to the quantum confinement effect, while the blue emission from Si-QDs is related to defect states at the newly formed silicon oxide surface.