Software-Escrow

Quellcodehinterlegung ist in Deutschland in den letzten Jahren zum üblichen Bestandteil eines wirksamen Risikomanagements geworden. Softwareh?user k?nnen davon genauso profitieren wie deren Kunden. Dieser Artikel erg?nzt auch den Artikel “Escrow Management bei elektronischer Archivierung” von Frau Rechtsanw?ltin Prof. Ursula Sury¹ um die rechtlichen und technischen Aspekte der Quellcodehinterlegung.     

Micro powder-injection moulding of metals and ceramics

Development of micro-MIM/-CIM was started at Forschungszentram Karlsrahe with the aim of creating a process suitable for a wide range of materials as well as for medium-scale and large-scale production of micro components. Using enhanced machine technology and special tempering procedures, this process enables the manufacturing of metal and ceramic devices with smallest wall thicknesses of 50 Μm and structural details of less than 3 Μm. Using ultrafine ceramic powders (e.g. zirconia) and high-quality LIGA mould inserts, surface qualities ofR _a = 40 nm or R_max ≤ 3 mm could be obtained. Possible practical applications are demonstrated by components of micro-annular gear pumps made of zirconia for future handling of very small volumes of dangerous fluids and micro samples (tensile and bending specimens) suitable for mechanical testing of metals (316L, 17-4PH) and ceramic materials (A1₂O₃, ZrO₂) in the micrometre range.     

Micro rotary swaging: process limitations and attempts to their extension

In this paper experimental investigations on micro components that are made by rotary swaging are presented and discussed. At first rotary swaging with its most important process variations is explained basically for the macro scale. Afterwards the fundamental changes of the forming of microcomponents are indicated as well as the smaller machines used henceforth. In this context, the shown process limitations and potential errors are very important. The change in microstructure after rotary swaging is shown in selected geometry and materials. The paper concludes with the planned experimental and analytic investigations as well as the machine design modifications for extension of the process limits of micro rotary swaging.     

Web-Roboter

Ohne Zusammenfassung Eingegangen am 02.04.1998     

Muscular involvement in Beh?et's disease: case report and review of the literature

Acute necrotizing myositis is described in a 22-yr-old man with clinically diagnosed Beh?et's disease. Light microscopic examination revealed a prominently granulocytic-monocytic infiltration of the muscle with severe necrosis. An infectious (bacterial, fungal or parasitic) etiology could be excluded by specific staining techniques and by immunohistochemistry. Vascular deposition of immune complexes was detected by direct immunofluorescence. Electron microscopy revealed severe structural damage and phagocytosis of muscle fibers. In the endomysium, leukocytes and occasional erythrocytes were found. Virus-like particles were not seen. The relevant literature on muscular involvement in Beh?et's disease is reviewed. It is suggested that two different stages of inflammation occur in Beh?et's disease. In the acute stage it presents as a granulocytic-monocytic necrotizing reaction developing from a neutrophil-mediated vasculitis. In the later phase lymphocytic infiltrations predominate. Despite the rare involvement of muscles the diagnosis of Beh?et's disease should be considered particularly in younger patients presenting with muscular symptoms like pain and swelling pre-dominantly of the lower extremities.     

Numerical solutions for unsteady flow in unconfined aquifers

Two numerical methods for solving the problem of unsteady flow in unconfined aquifers are studied. They are an explicit finite difference method (FDM), and the finite element method (FEM). The FEM is further subdivided into three schemes: vertical displacement approach, explicit scheme (FEM1), normal velocity approach, explicit scheme (FEM2), and vertical displacement approach, implicit scheme (FEM3). Results from the above methods are compared with experimental results from a sand box model. Various factors affecting the accuracy and numerical stability are investigated. Results indicate that, for a similar degree of accuracy, the FEM requires less computational effort than the explicit FDM. Amongst the three FEM schemes, FEM3 appears to be most attractive as it is the most stable and economical of the three schemes compared.     

Die berechnungskomplexität der symbolischen differentiation von interpolationspolynomen

Let a polynomial of degree n be given by its values at n+1 general points. Consider the problem of computing the values of its derivative at the same points (or at n of them). We show, that the minimum number of multiplications/divisions sufficient to solve this problem has the order of magnitude n log n.