1,721,032 research outputs found
Noisy characterization for CAD-oriented modeling of a pseudomorphic HEMT series versus frequency and temperature
No full textThe Kink Phenomenon in the Transistor S22: A Systematic and Numerical Approach
No full textThis letter provides a valuable technique for evaluating
the size and the shape of the kink effect in S22 for microwave
transistors. Since this phenomenon can be detected as the appearance of a concave shape in Im(S22) versus Re(S22), the second derivative of such a function is exploited for defining a set of parameters to fully and systematically characterize it. The effectiveness of the developed technique is demonstrated by its application to quantify the increase of the kink effect with the gate periphery for 0.15 um GaAs HEMTs
A New Millimeter Wave Small-Signal Modeling Approach for pHEMTs Accounting for the Output Conductance Time Delay
No full textA new technique is developed for determining analytically a millimeter wave small-signal equivalent circuit model of GaAs pHEMTs from Scattering parameter measurements. In order to obtain a good agreement between model simulations and measurements up to 90 GHz, the conventional intrinsic output conductance is substituted by a voltage controlled current source with a time delay. Consequently, a simple and accurate extraction procedure is proposed for taking into account the introduction of the output conductance time delay
Investigation on the non-quasi-static effect implementation for millimeter-wave FET models
No full textThe present article analyzes in detail different intrinsic small-signal models for transistors. Particular attention is devoted to the non-quasi-static effects, which play a crucial role at microwave and millimeter-wave frequencies. The advantages and disadvantages of these different equivalent circuit topologies are analyzed from both theoretical and experimental standpoints. This study clearly proves that best choice among these model representations depends on the specific device technology besides the investigated frequency range
microwave effects on isolated chick embrio heart
No full textThis study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the hear
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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