Deciding Effectively Propositional Logic Using DPLL and Substitution Sets

We introduce a DPLL calculus that is a decision procedure for the Bernays-Schönfinkel class, also known as EPR. Our calculus allows combining techniques for efficient propositional search with data-structures, such as Binary Decision Diagrams, that can efficiently and succinctly encode finite sets of substitutions and operations on these. In the calculus, clauses comprise of a sequence of literals together with a finite set of substitutions; truth assignments are also represented using substitution sets. The calculus works directly at the level of sets, and admits performing simultaneous constraint propagation and decisions, resulting in potentially exponential speedups over existing approaches.     

A physics-based electrical model of a magnetically sensitive AlGaN/GaN HEMT

Journal of Computational Electronics - The electrical model of a magnetically sensitive two-drain contact AlGaN/GaN HEMT (MagHEMT) is described for the first time and implemented in...     

LDMOSFET with drain potential suppression for 100 V Power IC technology

A standard 0.35 micrometer CMOS technology has been extended for 100 V Power IC applications by accommodating reduced surface field (RESURF) LDMOSFET device with p-well block region or extended poly-overlap region for suppression of the drain wrapping potential. A 100 V integrated H-bridge circuit suitable for driving a brushless DC motor has been designed, manufactured and tested to prove the technology. To streamline the design and integration of this power device 2D and 3D simulations have been performed. Different electrical isolation schemes to provide technology compartmentalization have also been investigated experimentally and results are discussed.     

Hydrothermal Changes of Starch Monitored by Combined NMR and DSC Methods

The thermal, dynamic, and structural properties of wheat starch–water systems with different levels of water content (11, 35, 40, 42, 45, and 50%, wet basis) were investigated. ¹H time domain nuclear magnetic resonance (TD-NMR) spectroscopy was used to interpret and quantify the water transfer and starch transformations in terms of water uptake, granule swelling, amylose leaching, and melting of starch polymers in relation to the different levels of water content. Complementary differential scanning calorimetry (DSC) experiments were performed to study the effects of water content on the degree of starch gelatinization. In particular, this twofold approach was applied to the first endotherm to study the mechanisms of gelatinization with a common heating range both in NMR and DSC. It was shown that the trend of the enthalpy changes in the first phase transition in starch–water (SW) mixtures was strongly correlated with the loss of solid content measured by NMR in the corresponding temperature range (55–70 °C). Based on the evolution of the relative amplitudes of T ₂, structural transformations of starch were shown to occur in both crystalline and amorphous regions within SW samples, supporting the fact that the amorphous phase of starch also plays a significant role in the phase transition of granules during gelatinization. This dynamic and hydrothermal approach provided the first NMR-based interpretation of the first endotherm measured by DSC.     

Chemical vapor synthesis of nanocrystalline perovskites using laser flash evaporation of low volatility solid precursors

One key requirement for the production of multinary oxide films by chemical vapor deposition (CVD) or nanocrystalline multinary oxides particles by chemical vapor synthesis (CVS) is the availability of precursors with high vapor pressure. This is especially the case for CVS where much higher production rates are required compared to thin films prepared by CVD. However, elements, which form low valent cations such as alkaline earth metals, are typically only available as solid precursors of low volatility, e.g., in form of beta-diketonates. This study describes laser flash evaporation as precursor delivery method for CVS of nanocrystalline perovskites. Laser flash evaporation exploits the nonequilibrium evaporation of solid metal organic precursors of low vapor pressure by absorption of the infrared radiation of a CO(2) laser. It is shown that stoichiometric, nanocrystalline particles consisting of SrZrO(3) and SrTiO(3) can be formed from corresponding mixtures of beta-diketonates which are evaporated nonselectively and with high rates by laser flash evaporation.