Wechselbeziehungen zwischen Physikalischer und Technischer Chemie

Interactions between physical and industrial chemistry. The most important interactions for the two areas of chemistry are found in the following three fields: (1)states of materials (states of aggregation) and thermodynamics; (2) kinetics of molecular processes as a basis for macroscopic models; (3) methods of testing and measurement and development of equipment. The ?classical state”? of each of these areas is first sketched out and then the principal developments which are still in course of flux; directions of future development are then deduced. Such directions are exposed to be: extension of the scope of application of supercritical states as solvents and reaction media, as part of a general expansion of industrial application of elevated pressures; increase in knowledge of nonlinear dynamics of chemical systems with regard to transient behaviour and control mechanisms; increase in basic research on molecular structure and dynamics at the interfaces of dispersed systems – especially micelles and catalyst surface – using ?in situ”? methods, and more extensive utilization of the results in industrial chemistry.     

Exact 3-satisfiability is decidable in time O(20.16254n)

Let F = C ₁ C _m be a Boolean formula in conjunctive normal form over a set V of n propositional variables, s.t. each clause C _i contains at most three literals l over V. Solving the problem exact 3-satisfiability (X3SAT) for F means to decide whether there is a truth assignment setting exactly one literal in each clause of F to true (1). As is well known X3SAT is NP-complete [6]. By exploiting a perfect matching reduction we prove that X3SAT is deterministically decidable in time O(2^0.18674n ). Thereby we improve a result in [2,3] stating X3SAT O(2^0.2072n ) and a bound of O(2^0.200002n ) for the corresponding enumeration problem #X3SAT stated in a preprint [1]. After that by a more involved deterministic case analysis we are able to show that X3SAT O(2^0.16254n ).An extended abstract of this paper was presented at the Fifth International Symposium on the Theory and Applications of Satisfiability Testing (SAT 2002).     

Third International Congress for Stereology

This article gives a survey of the actual experience with the relatively new technique of photo-emission electron microscopy. After describing the principal technique and the features of a modern high resolution instrument, the questions of image generation, contrast formation and resolution are considered. In particular the influence of the depth of information on resolution for flat polished sections is studied and some comparisons with the scanning electron microscope (SEM) are made.* The different fields of application of the photo-EEM are shown by examples.     

Wasserstoff-Energiewirtschaft aus kritischer Sicht

A critical view of the hydrogen economy . The goal of the hydrogen economy is to replace electrical energy, petroleum products, and natural gas wherever feasible by hydrogen as secondary energy. Apart from the coal the only primary energy source which be available in the near future will be nuclear energy, preferentially for supplying process heat for coal gasification (high temperature reactor). There will hardly be a future for thermochemical cyclic processes for cleavage of water; development of electrolytic process utilizing electrical energy from nuclear reactors appears technically and economically more promising. Exploitation of solar energy for generation of hydrogen appears unlikely in this century. The original concept of the hydrogen economy was associated with the discovery of hydrides of intermetallic compounds which are suitable for reversible storage of hydrogen. During the ensuing 15 years since the pioneering studies on this topic extensive detailed knowledge has accrued about the thermodynamic behaviour of hydride storage systems, their lattice structure, and the uptake and release of hydrogen. In any case, the hydrogen economy will be expensive with regard to both development and the necessary investment in this application.     

Der Einfluß einer langzeitigen Glühung bei 500 bis 700 °C auf das Kriechverhalten des Stahles 13 CrMo 4 4 bei 550 °C

Aufnahme von Zeit-Dehnung-Kurven über 1000 h bei 550 °C an einem Stahl mit 0,12% C, 0,86% Cr und 0,46% Mo nach 30- bis 10000 stündigem Glühen bei 500 bis 700 °C. Untersuchung der durch die Glühebehandlungen verursachten Änderungen im Feinbau des Werkstoffes durch Messung der Änderungen des elektrischen Widerstandes und der Koerzitivfeldstärke, durch Ermittlung der Streckgrenze und der Zugfestigkeit, durch lichtoptische Gefügebetrachtungen sowie durch chemische und röntgenographische Untersuchungen von Isolierungsrückständen.     

Erfassung,Beschaffung und Montage von Rohrleitungsteilen

Assessment, acquisition, and assembly of pipe components . Pipe technology accounts for ca. 30 to 35% of the planning of chemical plant and refineries. The reason for this high proportion lies in the numerous possibilities of variation. Each part must be defined, assessed and executed. The programme system developed consists of an assembly of several individual programmes which utilize available data. The overall procedure, from specification to assembly, is performed or supported by this programme system. The “general text system” (ATS) stores all pipe texts and pipe classes in several languages. With the aid of the “Lurgi piping macro-system” (LUROMAK ) the piping components are processed on the basis of flow charts, assembly plans and isometric drawings. The materials determined are transformed into buying information by the “execution system” (DISPO ). Registration of material entering and leaving stores in the “assembly organization system” (MOS) permits work preparation for assembly on the basis of the resulting stocks. It is also possible to assess the progress of assembly and to prepare costing information. The continuous processing of piping is permitted by a systematic standardization and classification, accomplished in particular by uniform definition of piping components in the ATS programme system.     

利用加密FPGA保护系统设计维护知识产权

随着半导体集成密度的提高及单位逻辑门成本的直线下降,使用可编程逻辑器件的系统所面对潜在的克隆和反向工程问题,已经成为真正的威胁.因此,系统设计人员必须时刻考虑知道产权保护问题及所用器件的保密性.采用非挥性Flash或反熔丝为基础的FPGA,对系统成本的影响甚微,却可提供高度的设计保密性.