An assessment of discretizations for convection-dominated convection–diffusion equations

The performance of several numerical schemes for discretizing convection-dominated convection–diffusion equations will be investigated with respect to accuracy and efficiency. Accuracy is considered in measures which are of interest in applications. The study includes an exponentially fitted finite volume scheme, the Streamline-Upwind Petrov–Galerkin (SUPG) finite element method, a spurious oscillations at layers diminishing (SOLD) finite element method, a finite element method with continuous interior penalty (CIP) stabilization, a discontinuous Galerkin (DG) finite element method, and a total variation diminishing finite element method (FEMTVD). A detailed assessment of the schemes based on the Hemker example will be presented.     

Three-dimensional Visualization of the Magnetic Microstructure in Bulk Fe-6.6 Pct Si

Magnetic materials such as Fe-Si alloys are magnetized by the rearrangement of their magnetic microstructure and domain wall motion. Understanding magnetic microstructures in the interior of a ferromagnet is essential for the control and reduction of energy losses in electrical devices. The three-dimensional magnetic microstructure of solids is still unknown due to the lack of an appropriate observation technique, and the magnetic domain wall structure inside a ferromagnet has never been observed with sufficiently high resolution. The first observation of the 3D magnetic microstructure of an Fe-6.6 pct Si alloy with a high spatial resolution is reported. The domain walls known to exist inside positive anisotropy cubic materials, i.e., the 180-deg domain walls and the 90-deg domain walls, were analyzed for the first time. The structure and orientation of the domain walls were found to be very different from the prediction of current theoretic models.     

Electrochemical and DFT-studies of substituted thiophenes

UV-vis absorption spectra and cyclic voltammograms of a selection of substituted thiophenes and their oligomers carrying trifluoracetyl acetone functional groups have been obtained. A comparison with calculated values of HOMO-LUMO energies (the former corresponding to the ionization potentials E_i) shows strong correlations between calculated and experimentally obtained data; they are in close agreement with estimates in terms of electron-donating and -withdrawing effects from an empirical point of view.     

Distribution of the carbide phase in the viscoplastic layer during the rotational friction-welding of various steels

The paper presents the viscoplastic phenomena observed during the rotational friction-welding process of high-speed steel M2 (AISI SAE) with carbon steel 1060 (AISI SAE). The structure, phase composition and distribution of the carbide phase in the friction plane and adjoining zones are examined by using optical microscopy (OM) with a system for quantitative analysis, and scanning electron microscopy (SEM) in addition to EDS analysis. The experimentally-checked mathematical relationship is suggested for the calculation of the radial movements of the carbide phase, immediately next to the friction plane. On the basis of qualitative and quantitative evaluation of the microstructural and rheological appearances, a model of carbide phase distribution is also established in the viscoplastic and viscous layers in the area of the friction plane.     

面向小功率驱动应用的新型SOI驱动器和SmartPACK／Smart PIM模块

本文基于SOI技术,开发了一款新型的600V/0.3A 6-pack IGBT/MOSFET驱动器芯片.此款名为6ED003L06-F的芯片集成了三相电平转换、门极驱动和电路保护等诸多特性，在缩小芯片尺寸的同时也提高了性能，例如抗反相瞬态电压的鲁棒性等。另外，本文还利用该SOI驱动芯片开发了SmartPACK/SmartPIM系列新型IPM模块，该模块在一块基于DCB层的底板上集成了SOI驱动器，600V IGBT3和自举功能，并且无须支承板。这种IPM可对应6A-12A的额定电流，同时具有结构紧凑、成本低廉、操作简单等优点，适用于各类小功率驱动特别是消费类驱动应用。     

Preliminary animal pharmacokinetics of the parenteral antifungal agent MK-0991 (L-743,872)

MK-0991 (L-743,872) is a potent antifungal agent featuring long half-life pharmacokinetics. The pharmacokinetics of MK-0991 administered intravenously to mice, rats, rhesus monkeys, and chimpanzees is presented. Unique to MK-0991 is its consistent cross-species performance. The range of values for the pharmacokinetic parameters were as follows: clearance, 0.26 to 0.51 ml/min/kg; half-life, 5.2 to 7.6 h; and distributive volume, 0.11 to 0.27 liters/kg. The level of protein binding of MK-0991 was determined to be 96% in mouse and human serum. The compound exhibited high affinities for human serum albumin and at least two lipid components. The rationale for the selection of MK-0991 as a drug development candidate was based on its two- to threefold superior pharmacokinetic performance in chimpanzees over the performance of an otherwise equivalent analog, L-733,560. Once-daily dosing for MK-0991 is indicated by a graphical comparison of levels in the circulations of chimpanzees and mice. In a study of the pharmacokinetics of MK-0991 in mouse tissue, the organs were assayed following intraperitoneal administration. The area under the concentration-versus-time curves (AUC) segregated the tissues into three exposure categories relative to plasma. The tissues with greater exposure than that for plasma were liver (16 times), kidney (3 times), and large intestine (2 times). The exposure for small intestine, lung, and spleen were equivalent to that for plasma. Organs with lower levels of exposure were the heart (0.3 times that for plasma), thigh (0.2 times), and brain (0.06 times). Kinetically, drug was cleared more slowly from all tissues than from plasma, indicating that terminal-phase equilibrium had not been achieved by 24 h. Thus, some measure of accumulation is predicted for all tissues. Single daily doses of MK-0991 should provide adequate systemic levels of fungicidal activity as a result of its long half-life pharmacokinetics, wide distribution, and slowly accumulating concentrations in tissue.     

Die zeitliche Hysterese der Ladungen bei elektrischen Gleitentladungen

Zusammenfassung Überlagert man innerhalb t s bei gleichbleibender Elektrodenspannung und im Bereiche des Gebietes mit überwiegender Ladungshysterese zwei gleitende Entladungen, so wird die Ausdehnung der zweiten durch die Hysterese der Ladungen verkürzt. Die Verkürzung hängt von der Zeitdifferenz der Aufeinanderfolge nach einem Exponentialgesetz ab [vgl. Gl. (1)].Dieses Ladungshysteresegesetz gilt für Polbüschel (Klydonograph), Gleitbüschel und Gleitfunken und wurde ermittelt bis zu einem Spannungsbereich von etwa 40 kV. Im Grenzfall kleinster Zeitdifferenz wird die Verkürzung 1/3 sowohl bei positiven als auch bei negativen Entladungen.An Hand der Versuchsergebnisse gewinnt man einen Einblick in den zeitlichen Abbau (durch Oberflächenleitung, Dissoziation in den Raum, Ionenfang u. dgl.) der nach vollendetem Aufbau der Entladung entstandenen Restladung.Die Messungen zu vorliegender Arbeit wurden im Institut für theoretische Physik an der Technischen Hochschule Dresden ausgeführt.Herrn Prof. Dr. Toepler bin ich für wertvolle Anregung zu dieser Arbeit zu Dank verpflichtet.