ANN Model For SiGe HBTs Constructed From Time-Domain Large-Signal Measurements

We construct a large-signal artificial neural network (ANN) model for SiGe HBTs, directly from time-domain large-signal measurements. It is known that HBTs are very sensitive to self-heating and therefore we explicitly study the effect on the model accuracy of the incorporation of the self-heating effect in the behavioural model description. Finally, we show that this type of models can be accurate at extreme operating conditions, where classical compact models start to fail

Correlation between the reliability of HEMT devices and that of a combined oscillator-amplifier

We evaluate an oscillator-amplifier MMIC submitted to high-temperature operating life time tests. To relate adequately these results with individual components’ results, it is important to realise that failure mechanisms in non-linear MMICs are governed by the maximally instantaneous voltages/currents and hence that comparisons should be conducted at equal instantaneous conditions

Computation of Conductance and Capacitance for IC Interconnects on a General Lossy Multilayer Substrate

In this paper a simple method for analysis and modelling of transmission interconnect lines on general lossy multilayer substrates at high bit rates is presented. The analysis is based on semi-analytical Green's function approach and recurrence relation between the coefficients of potential in n and n + 1 layers, respectively. The electromagnetic concept of free charge density is applied. It allows us to obtain integral equations between electric scalar potential and charge density distributions. These equations are solved by the Galerkin procedure of the Method of Moments. New approach is especially adequate to model 2-D layered structures with planar boundaries for frequencies up to 20GHz (quasistationary field approach). The transmission line parameters (capacitance and conductance per unit length) for the given interconnect multilayer geometry are computed. A discussion of the calculated line admittance in terms of technological and geometrical parameters of the structure is given. A comparison of the numerical results from the new procedure with the techniques presented in the previous publications are provided, too

Analysis of Coplanar On-Chip Interconnects on Lossy Semiconducting Substrates

In this paper, a method for analysis and modeling of coplanar transmission interconnect lines that are placed on top of silicon-silicon oxide substrates is presented. The potential function is expressed by series expansions in terms of solutions of the Laplace equation for each homogeneous region of layered structure. The expansion coefficients of different series are related to each other and to potentials applied to the conductors via boundary conditions. In the plane of conductors, boundary conditions are satisfied at Nd discrete points with Nd being equal to the number of terms in the series expansions. The resulting system of inhomogeneous linear equations is solved by matrix inversion. No iterations are required. A discussion of the calculated line admittance parameters as functions of width of conductors, thickness of the layers, and frequency is given. The interconnect capacitance and conductance per unit length results are given and compared with those obtained using full wave solutions, and good agreement have been obtained in all the cases treated

Constitutive activation and accelerated maturation of peripheral blood t cells in healthy adults in burkina faso compared to Germany: The case of malaria?

<p>Abstract</p> <p>Objective</p> <p>It is not exactly known how frequent exposure to <it>Plasmodium falciparum </it>shapes the peripheral blood T-cell population in healthy West Africans.</p> <p>Methods</p> <p>The frequency of peripheral blood CD4⁺lymphocytes responding to <it>Plasmodium falciparum </it>merozoite surface protein 1 <it>(Pf</it>MSP-1) by production of interferon-gamma (IFN-γ), interleukin-2 (IL-2) or tumor necrosis factor-alpha (TNF-α) was determined using a commercially available flow cytometric activation assay (Fastlmmune) in 17 healthy adults in Nouna, Burkina Faso. T-cell activation and maturation in peripheral blood of healthy adults in Burkina Faso (n = 40) and Germany (n = 20) were compared using immunophenotyping and three-colour flow cytometry.</p> <p>Results</p> <p>Significant numbers of <it>Pf</it>MSV-1 -specific CD4⁺lymphocytes producing IFN-γ, IL-2 and/or TNF-α were detected in 14 healthy adults in Nouna. Cytokine profiles showed predominant production of IFN-γ and TNF-α. Compared to Germans, Burkinabé showed markedly lower proportions of CCR7⁺CD45RA⁺naïve CD4⁺cells and slightly higher frequencies of CD95⁺CD4⁺T-cells and of CD38⁺CD8⁺T-cells. The median antibody-binding capacity of CD95^dimCD4⁺T-cells in Burkinabé was more than twice the value observed in Germans (263 vs. 108 binding sites per cell, p < 0.0001).</p> <p>Conclusions</p> <p>We hypothesize that an IFN-γ-induced increase in the expression level of CD95 on CD4⁺lymphocytes may lower the activation threshold of resting naïve CD4⁺T-cells in healthy adults living in Burkina Faso. Bystander activation of these cells deserves further study as a molecular mechanism linking strong IFN-γ responses against <it>Plasmodium falciparum </it>to decreased susceptibility to parasitemia observed in specific ethnic groups in West Africa.</p