Development and fabrication of improved power transistor switches

A new class of high-voltage power transistors was achieved by adapting present interdigitated thyristor processing techniques to the fabrication of npn Si transistors. Present devices are 2.3 cm in diameter and have V sub CEO (sus) in the range of 400 to 600V. V sub CEO (sus) = 450V devices were made with an (h sub FE)(I sub C) product of 900A at V sub CE = 2.5V. The electrical performance obtained was consistent with the predictions of an optimum design theory specifically developed for power switching transistors. The device design, wafer processing, and assembly techniques are described. Experimental measurements of the dc characteristics, forward SOA, and switching times are included. A new method of characterizing the switching performance of power transistors is proposed

Coverage statistics for sequence census methods

Background: We study the statistical properties of fragment coverage in genome sequencing experiments. In an extension of the classic Lander-Waterman model, we consider the effect of the length distribution of fragments. We also introduce the notion of the shape of a coverage function, which can be used to detect abberations in coverage. The probability theory underlying these problems is essential for constructing models of current high-throughput sequencing experiments, where both sample preparation protocols and sequencing technology particulars can affect fragment length distributions. Results: We show that regardless of fragment length distribution and under the mild assumption that fragment start sites are Poisson distributed, the fragments produced in a sequencing experiment can be viewed as resulting from a two-dimensional spatial Poisson process. We then study the jump skeleton of the the coverage function, and show that the induced trees are Galton-Watson trees whose parameters can be computed. Conclusions: Our results extend standard analyses of shotgun sequencing that focus on coverage statistics at individual sites, and provide a null model for detecting deviations from random coverage in high-throughput sequence census based experiments. By focusing on fragments, we are also led to a new approach for visualizing sequencing data that should be of independent interest.Comment: 10 pages, 4 figure

Research in constraint-based layout, visualization, CAD, and related topics : a bibliographical survey

The present work compiles numerous papers in the area of computer-aided design, graphics, layout configuration, and user interfaces in general. There is nearly no conference on graphics, multimedia, and user interfaces that does not include a section on constraint-based graphics; on the other hand most conferences on constraint processing favour applications in graphics. This work of bibliographical pointers may serve as a basis for a detailed and comprehensive survey of this important and challenging field in the intersection of constraint processing and graphics. In order to reach this ambitious aim, and also to keep this study up-to-date, the authors appreciate any comment and update information

¿Son suficientes las competencias exigidas en el decreto 2539 de 2005 para un buen desempeño del servidor público?

El estudio objeto del presente ensayo es revisar, si son suficientes las competencias exigida en el decreto 2539 de 2005, que como mínimo deben poseer la servidores públicos para el ejercicio de sus funciones, conforme a lo exigido por el Ejecutivo o si por el contrario, con miras a lograr una gestión pública exitosa, seria necesario el estudio y la adición de algunas competencias adicionales a las ya exigida

Science in the Elementary and Middle School: Earth and Space Science Starting Points

This chapter focuses on students' alternative conceptions of science that create a barrier to learning concepts in Earth and space science. Using specific examples of basic content and concepts addressing elementary and middle school, a strategy for identifying and addressing alternative conceptions is demonstrated. Examples of discrepant event activities and learning cycle lesson plans are provided. These discussions provide a foundation for teachers who wish to effectively plan lessons that assist students in their learning of Earth and space science concepts. Educational levels: Graduate or professional

The automatic orienting of attention to goal-relevant stimuli

It is often assumed that attention is automatically allocated to stimuli relevant to one’s actual goals. However, the existing evidence for this idea is limited in several ways. We investigated whether words relevant to a person’s current goal influence the orienting of attention even when an intention to attend to the goal-relevant stimuli is not present. In two experiments, participants performed a modified spatial cueing paradigm combined with a second task that induced a goal. The results of the experiments showed that the induced goal led to the orientation of attention to goal-relevant words in the spatial cueing task. This effect was not found for words semantically related to the goal-relevant words. The results provide evidence for motivational accounts of attention, which state that the automatic allocation of attention is guided by the current goals of a person

Variations in chemistry of macerals as refl ected by micro-scale analysis of a Spanish coal

An Oligocene lignite (Ebro Basin, Spain) and its density fractions were analyzed petrographically and with microscale techniques (electron microprobe and micro-FTIR) to gain insight into differences between individual macerals of low rank high-sulfur coal. The density of the alginite-dominated fraction is below 1.26g/cm3, and that of the huminite-dominated fraction is above 1.38g/cm3. Densities within 1.26-1.38g/cm3 represent mixtures of liptinite and huminite macerals. With regard to elemental composition, alginite has the highest carbon content (75.6% on average) and the lowest oxygen content (6.1% on average). Corpohuminite is characterized by the lowest carbon content (62.3% on average) and the highest oxygen content (21.5% on average). Nitrogen contents for corpohuminite and ulminite (~1%) are similar, but are significantly lower in alginite (0.2% on average). Sulfur content is highest in alginite (13.4% on average), followed by corpohuminite (9.8%) and ulminite (7.7%). Functional group analysis documents large differences between macerals of the huminite and liptinite group, but also indicates differences between individual macerals within both the huminite and liptinite group. These ifferences are most notable in aromaticity, degree of aromatic ring condensations, and hydrocarbon potential