MiniSKiiPIPM—面向中等功率应用的先进模块架构

电力电子技术可以帮助提高能源效率和节约大量能源,尤其是在中等功率应用市场中。得益于其高集成度和简单的组装,本文所介绍的600V智能IGBT功率模块能够促进电力电子的应用。该模块的特点在于其基于双极性电平转换器的先进概念。因此,所集成SOI驱动器不受参考电压变化的影响,输出功率高达15kW,从而提高了在应用中的可靠性。     

MiniSKii PIPM面向中等功率应用的先进模块架构

电力电子技术可以帮助提高能源效率和节约大量能源,尤其是在中等功率应用市场中。得益于其高集成度和简单的组装,本文所介绍的600V智能IGBT功率模块能够促进电力电子的应用。该模块的特点在于其基于双极性电平转换器的先进概念。因此,所集成SOI驱动器不受参考电压变化的影响,输出功率高达15kW,从而提高了在应用中的可靠性。     

Efficient location aware intrusion detection to protect mobile devices

This paper addresses the problem of efficient intrusion detection for mobile devices via correlating the user’s location and time data. We developed two statistical profiling approaches for modeling the normal spatio–temporal behavior of the users: one based on an empirical cumulative probability measure and the other based on the Markov properties of trajectories. An anomaly is detected when the probability of a particular (location, time) evolution matching the normal behavior of a given user becomes lower than a certain threshold, determined by controlling the recall rate of the model of the normal user’s behavior. We used compression techniques to reduce processing overhead while maintaining high accuracy. Our evaluation based on the Reality Mining and Geolife data sets shows that the proposed system is capable of detecting a potential intrusion within 15 min and with 94 % accuracy.     

Investigations on calcium carboxylate and sulfonate additive incompatibilities in a preservation oil

Severe quality defects of a well‐established preservation oil ranging from improper viscosity values to the formation of calcium carboxylate precipitates led to detailed investigations on the origin of these failures. Chemical analyses employing spectroscopic and chromatographic techniques focusing on the product's additives were performed. Thereupon, a mechanism for precipitate formation based on a delicate interaction between solubilizer, carboxylates, sulfonates and calcium ions was proposed. For this mechanism, ligand properties of sulfonates play a vital role: In contrast to monosulfonates, disulfonates seem to impede precipitation of calcium carboxylates. Copyright © 2014 John Wiley & Sons, Ltd.     

Reliability of spring pressure contacts under environmental stress

Spring contacts are an excellent solution for connecting a power module with a printed circuit board (PCB). They can be applied in a wide current range from sensor currents of a few milliamps to load currents of several amps. They offer many advantages like easy assembly without soldering and also easy disassembly for maintenance purposes. The reliability of spring contacts under environmental stress by mechanical wear, rapid temperature change and corrosive atmosphere is significant for the application. The experimental results presented in this paper certify that spring contacts are reliable even under harsh environmental conditions.     

Chemical composition and antibacterial activity of Laurus nobilis essential oil towards foodborne pathogens and its application in fresh Tuscan sausage stored at 7 °C

The presence of foodborne pathogens in fresh Tuscan sausage has been reported and these contaminations pose a potential risk to consumers. The objective of the present study was to evaluate the antimicrobial activity of bay leaf essential oil (EO) in vitro and in fresh Tuscan sausage stored at 7 °C for 14 d. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against foodborne pathogens were determined in vitro. The lowest MIC and MBC were found for Escherichia coli (MIC = MBC = 2.5 g/L) and Yersinia enterocolitica (MIC = 1.25 g/L, MBC = 2.5 g/L). Fresh Tuscan sausages were treated with bay leaf EO at 0.05 g/100 g or 0.1 g/100 g and their shelf life was compared to a non-treated control. All groups presented low levels of rancidity (TBARS < 0.5 mg MDA/kg). The EO was able to reduce the population of total coliforms (2.8 log CFU/g) and to extend the product shelf life for two days. Although the presence of the EO affected the sensory characteristics of the sausage, it was considered acceptable by consumers at both concentrations tested. Overall, the results of this study indicate that bay leaf essential oil can be applied in fresh Tuscan sausage to improve its safety and shelf life.     

Resistive Random Access Memory Cells with a Bilayer TiO2/SiOX Insulating Stack for Simultaneous Filamentary and Distributed Resistive Switching

In order to fulfill the information storage needs of modern societies, the performance of electronic nonvolatile memories (NVMs) should be continuously improved. In the past few years, resistive random access memories (RRAM) have raised as one of the most promising technologies for future information storage due to their excellent performance and easy fabrication. In this work, a novel strategy is presented to further extend the performance of RRAMs. By using only cheap and industry friendly materials (Ti, TiO₂, SiO_X, and n⁺⁺Si), memory cells are developed that show both filamentary and distributed resistive switching simultaneously (i.e., in the same I–V curve). The devices exhibit unprecedented hysteretic I–V characteristics, high current on/off ratios up to ≈5 orders of magnitude, ultra low currents in high resistive state and low resistive state (100 pA and 125 nA at –0.1 V, respectively), sharp switching transitions, good cycle‐to‐cycle endurance (>1000 cycles), and low device‐to‐device variability. We are not aware of any other resistive switching memory exhibiting such characteristics, which may open the door for the development of advanced NVMs combining the advantages of filamentary and distributed resistive switching mechanisms.     

Least squares timestamp synchronization for local broadcast networks

The analysis of computer network experiments strongly relies on event log files recorded by the participating network nodes during the experiment. Timing related issues play an important role here for a number of central parameters like, e.g., end-to-end delay. As each node uses its local clock to timestamp the events in the log files, the large deviation of standard crystal oscillator based clocks imposes some big problems. We look at this issue in the case of networks with local broadcast media, where occurring transmissions can often be observed by multiple network nodes. We have developed a method to correct the timestamps in such an environment in a previous paper. Here, we present a second solution. For this new solution, we give bounds on the synchronization quality and compare the two approaches by means of simulation.     

Visuelle Textanalyse Interaktive Exploration von semantischen Inhalten

Methoden und Techniken zur automatischen Verarbeitung und inhaltlichen Erfassung gro?er Mengen an Textdokumenten haben in den vergangenen Jahren enorm an Bedeutung gewonnen. W?hrend einerseits die Verfügbarkeit und der Zugang zu digitalisierten Textdokumenten bis dato in ungeahntem Ma?e gestiegen sind, erweist sich die Erfassung des semantischen Inhalts solcher Dokumentsammlungen als problematisch. Dem expandierenden Forschungsfeld der visuellen Textanalyse und Textvisualisierung kommt dabei eine Schlüsselrolle bei der L?sung von Problemstellungen aus der Praxis zu. Anhand aktueller Anwendungsbeispiele und einem überblick über den Stand der Forschung erl?utert dieser Artikel die vielf?ltigen M?glichkeiten, die sich durch visuelle Textanalyse ergeben.     

Power cycling results for different control strategies

Power cycling is an important method to characterize the lifetime of power semiconductor modules. Application engineers use lifetime curves published by manufacturers to verify that their system design meets the required reliability. An important condition for the lifetime of a module under repeated temperature swings is the control strategy applied during the test. Power cycling tests with identical start condition but different control strategies have been performed, which have been conducted on specially assembled test equipment with ultimate control of all test parameters. The results show, that different control strategies deliver lifetime results that vary by a factor of 3.