Direct parameter-extraction method for HBT small-signal model

An accurate and broadband method for the direct extraction of heterojunction bipolar transistor (HBT) small-signal model parameters is presented in this paper. This method differs from previous ones by extracting the equivalent-circuit parameters without using special test structures or global numerical optimization techniques. The main advantage of this method is that a unique and physically meaningful set of intrinsic parameters is extracted from the measured S-parameters for the whole frequency range of operation. The extraction procedure uses a set of closed-form expressions derived without any approximation. An equivalent circuit for the HBT under a forward-bias condition is proposed for extraction of access resistances and parasitic inductances. An experimental validation on a GaInP/GaAs HBT device with a 2×25 μm emitter was carried out, and excellent results were obtained up to 30 GHz. The calculated data-fitting residual error for three different bias points over 1-30 GHz was less then 2%     

AC actuation contribution to the induced electromotive force in the miniaturized inductive planar microphone

In this paper, we aim to analyze the gain ratio in the output induced voltage of a CMOS-compatible miniaturized electrodynamic microphone which is based on the use of two coplanar concentric inductors. These latter are comparable to a concentric transformer with a secondary situated on the microphone diaphragm top. The study has been applied when the outer inductor is actuated using an AC bias instead of DC leading to a time-variable B-field. The induced output voltage expression has been evaluated using two distinct analytic methods: the magnetic field derivation and the electric field approach. When an AC current with frequency above that of the acoustic band is used to bias the primary, results show that the induced voltage increases and becomes independent from the incident pressure wave frequency. The paper demonstrates also that with an AC bias, the microphone induced voltage values can reach the order of hundreds of µVs, as opposed to only few µVs when applying a DC bias. The gain in the induced voltage has been investigated and it is shown that it can be correlated to the AC current frequency, ω_c, and the inner inductor fluctuation frequency, ω_p. Moreover, this has been quantified analytically and it is shown that it equals ω_c/8ω_p. This result will not only enhance the overall performance of the microphone, but will also make the preamplification design less complicated by increasing the SNR ratio.     

Impact of Ground‐State Charge Transfer and Polarization Energy Change on Energy Band Offsets at Donor/Acceptor Interface in Organic Photovoltaics

The fullerene (C₆₀)/copper phthalocyanine (CuPc) interface is one of the widely used donor/acceptor (DA) interfaces for organic photovoltaics (OPVs), and information on the electronic structure at the interface is essential for fully understanding the energetics of excitons and carriers in OPVs. Here, an investigation into the energy levels at the C₆₀/CuPc interface is made using UV photoelectron, X‐ray photoelectron, and inverse photoemission spectroscopies. The vacuum level and core levels rise with C₆₀ deposition on the CuPc film, which indicates that the interfacial dipole is formed with the negative charge on the C₆₀ side. The interfacial dipole can be formed by the electron transfer from CuPc to C₆₀ in the ground state at the interface, which is indicated by the analysis of the UV–vis–NIR absorption spectrum of the CuPc/C₆₀ blended film. On the other hand, the highest occupied and lowest unoccupied molecular orbitals of CuPc and C₆₀ shift in opposite directions at the interface. This is attributed to the changes of the polarization energies of CuPc and C₆₀ at the interface. The formation of the interfacial dipole and the change of the polarization energy result in the anomalous energy band offsets at the C₆₀/CuPc interface, which are entirely different from those in inorganic p–n junctions.     

Changes in laryngeal muscle activities during hypercapnia in the cat

This article reports two studies aimed at validating the 25-item self-report McGreal and Joseph (1993) Depression-Happiness Scale (D-H S). In the first study, principal component data are reported on the D-H S with 194 respondents. A forced 1-factor solution confirmed the unidimensionality of the scale (item loadings ranged from .38 to .77) and thus the feasibility of a statistically bipolar measure. In the second study, data on the convergent validity of the D-H S with the Beck Depression Inventory (r=-.75) and the Oxford Happiness Inventory (r=.59) with 100 respondents are reported confirming the construct validity of the scale. Implications for research in social and clinical psychology are discussed along with the possible uses of the D-H S in a clinical setting.     

Detection of Salient Curvature Features on Polygonal Surfaces

We develop an approach for stable detection of perceptually salient curvature features on surfaces approximated by dense triangle meshes. The approach explores an area degenerating effect of the focal surface near its singularities and combines together a new approximations of the mean and Gaussian curvatures, nonlinear averaging of curvature maps, histogram-based curvature extrema filtering, and an image processing skeletonization procedure adapted for triangular meshes. Finally we use perceptually significant curvature extrema triangles to enhance the Garland-Heckbert mesh decimation method.     

High-response flux control of direct-field-oriented induction motorwith high efficiency taking core loss into account

Stator core loss has significant adverse effects when an induction motor is controlled by the conventional field-oriented method. Therefore, taking core loss into account should make it possible to control the torque very precisely. In this paper, a direct-field-oriented induction motor with a deadbeat rotor flux controller was developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Simulation and experimental results have demonstrated that this method has higher efficiency and good speed response without any degradation in the transient characteristics     

Comparison between old and new methods for detection of allergenic substances (egg and milk)

The old ELISA method for detection of allergenic substances (egg and milk) in Kanagawa prefecture from 2003 to 2007, employed before improvement of the food allergen labeling system, yielded detection rates of 20% for egg and 30% for milk. In 2005, after improvement of the labeling system, the detection rate using the new ELISA in solutions containing 1% SDS and 7% 2-mercaptoethanol increased by about 10% for egg, but decreased by half for milk. There were 4 positive samples (over 10 μg/g) for both egg and milk proteins, on account of contamination by ingredients at the manufacturing line and the lack of proper food labeling. In 2009, the contamination levels of egg and milk proteins in labeled commercial foods were low. In a comparison between the new and old methods with the same samples, both the new ELISA and Western-blot analyses showed an increase in the detection rate of egg protein. In relation to milk protein, the detection rates were decreased with the new ELISA, although the ELISA detection rate and consistency rates with Western-blot analysis were increased. On the other hand, in the case of a protein content below 5 μg/g, it was impossible to determine ovomucoid and casein by Western-blot analysis.