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This paper reviews the current state of loudspeaker-based spatial sound reproduction methods from technical perspective as well as perceptual perspective. A nomenclature is developed that allows for a strict separation between the...
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This paper reviews the current state of loudspeaker-based spatial sound reproduction methods from technical perspective as well as perceptual perspective. A nomenclature is developed that allows for a strict separation between these two perspectives. The physical fundamentals, practical realization, and results from perceptual studies are discussed for a number of well-established and emerging reproduction techniques. Further, the paper outlines novel approaches to spatial sound evaluation in terms of perceived quality and provides a comparison of current approaches.
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This paper proposes a unified comprehension of the isothermal ceramic process kinetics stemming from mesoscopic irreversible thermodynamics. Accordingly, a unified process kinetic equation (UPKE) is derived, which predicts that th...
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This paper proposes a unified comprehension of the isothermal ceramic process kinetics stemming from mesoscopic irreversible thermodynamics. Accordingly, a unified process kinetic equation (UPKE) is derived, which predicts that the global isothermal process rate of any ceramic process is, in general, nonlinearly related both to its activation energy and its affinity. Nevertheless, for a low-affinity ceramic process conducted either in a field-free or resonant wave-field condition, its global isothermal rate, according to the proposed UPKE, is approximately linearly related to its affinity in the spirit of Fick's diffusion law. Therefore, the rate enhancement of a low-affinity process occurring in any resonant wave-field may be caused either by a reduction in activation energy, as in microwave-enhanced sintering, or by activation energy reduction along with an affinity augmentation, as in microwave-assisted glass-crystallization. Conversely, for a high-affinity ceramic process, e.g., a chemical reaction, the 'degenerate' UPKE predicts that its kinetics is exclusively dictated by the activation energy in the spirit of Arrhenius's rate law. Hence, isothermal rate enhancements of chemical reactions in ceramic processing under resonant wave-field conditions are believed to predominantly result from a field-induced reduction in activation energy.
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An optimization-based field synthesis approach is presented that employs a hierarchical plane wave-based field transformation concept for efficient evaluation of the inverse problem forward operator. Irregular transmit antenna arr...
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An optimization-based field synthesis approach is presented that employs a hierarchical plane wave-based field transformation concept for efficient evaluation of the inverse problem forward operator. Irregular transmit antenna array configurations can be used to synthesize a target field distribution in an arbitrarily shaped test volume with full consideration of the antenna element radiation characteristics. For this purpose, a triangular mesh forms the test zone boundary surface on which Rao–Wilton–Glisson (RWG) vector-basis functions perform electric and magnetic field testing. An iterative Krylov subspace solver is employed to solve the ill-posed inverse problem for the transmit antenna coefficients. The effectiveness, accuracy, and efficiency of the proposed field synthesis algorithm are demonstrated for configurations with test zone extents of up to one hundred wavelengths. Moreover, the approach is utilized for antenna measurements, where antenna near-fields are transformed into far-fields.
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The effect of electrode work function (WF) on the device resistance of carbon-nanotube field-effect transistors (CNT-FETs) is less significant than that of device surface chemistry, specifically interactions with molecular oxygen...
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The effect of electrode work function (WF) on the device resistance of carbon-nanotube field-effect transistors (CNT-FETs) is less significant than that of device surface chemistry, specifically interactions with molecular oxygen adsorbate. Experimental results are based on over 130 individual devices with electrode WFs varying from 4.17 to 5.21 eV that were tested under standard-atmosphere, ultrahigh-vacuum, and pure-oxygen environments. Oxygen decreased device resistance by an average of 56% and altered majority charge carriers regardless of electrode metal. Variations in CNT-FET performance based on electrode material appeared more closely associated with crystallization and oxidation states than WF.
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A sound field recording and reproduction method that exploits prior information on the locations of sound sources to be reproduced is proposed. Current methods do not take such prior information into consideration in the transform...
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A sound field recording and reproduction method that exploits prior information on the locations of sound sources to be reproduced is proposed. Current methods do not take such prior information into consideration in the transformation from the signals received by microphones into the driving signals of loudspeakers. The proposed method for planar and linear arrays of microphones and loudspeakers optimizes spatial basis functions and their coefficients, which represent the driving signals of loudspeakers, on the basis of the maximum a posteriori (MAP) estimation approach, leading to higher reproduction accuracy above the spatial Nyquist frequency when there are fewer microphones than loudspeakers, i.e., super-resolution in sound field recording and reproduction. Numerical simulations show that the reproduction accuracy at frequencies above the spatial Nyquist frequency was maintained using the proposed method even when there was a mismatch between actual and prior locations of the sound sources to be reproduced.
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This study aimed the optical imaging of malignant and normal skin tissues with multimodal wide-field fluorescence polarization imaging (WF) technique, by using methylene blue as fluorescence dye. We present optical imaging of skin...
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This study aimed the optical imaging of malignant and normal skin tissues with multimodal wide-field fluorescence polarization imaging (WF) technique, by using methylene blue as fluorescence dye. We present optical imaging of skin tissues by different techniques, including reflectance, fluorescence, and polarization imaging for early detection of skin cancer. We collected the reflectance confocal images at 390 and 500 nm. For wide-field fluorescence images, specimens were stimulated at 640 nm and images were collected between 670 and 710 nm. The correlation of the regarded optical modalities with histopathology (H&E), their potentials, capabilities, and limitations to detect skin lesions are discussed. The advantages of multimodal imaging of skin tissues are analyzed to divulge possibilities for precise tumor boundary detection and their classification for malignant and nonmalignant skin tissues. Prior to imaging, the cells were stained in aqueous MB (a dye approved by FDA).
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The effect of meridional circulation on spherical shell dynamos is considered in the Parker approximation. We demonstrate that the type of the exited solution crucially depend on the intensity of the meridional circulation. If the...
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The effect of meridional circulation on spherical shell dynamos is considered in the Parker approximation. We demonstrate that the type of the exited solution crucially depend on the intensity of the meridional circulation. If the circulation is equatorward or if it is polarward however do not exceed some critical value, an oscillating solution in form of an equatorward traveling wave is excited. If the polarward meridional circulation becomes too intensive the solution becomes steady growing. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Magnetosphere-ionosphere coupling is representative of a class of astrophysical problems involving the interaction between very different plasma regimes that are connected by magnetic fields. It is a major issue of the planet's (e...
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Magnetosphere-ionosphere coupling is representative of a class of astrophysical problems involving the interaction between very different plasma regimes that are connected by magnetic fields. It is a major issue of the planet's (e.g., Earth, Jupiter, Saturn) system how the magnetospheric plasma is coupled to the planet's ionosphere/atmosphere. Due to their roles on energy transport and conversion in the terrestrial magnetosphere, dipolarization fronts (DFs) in the magnetotail have been intensively studied. While the energy may also be transported toward the ionosphere during the magnetosphere-ionosphere coupling, the coupling processes during DF events remain unclear. Using high-quality MMS and Swarm measurements, we present new conjugated observations of ultralow-frequency waves associated with the DF in the magnetotail and multiscale field-aligned currents (FACs) in the ionosphere. The tail large-amplitude low-frequency magnetic disturbances and associated FACs were found connected with a pair of ionospheric FACs near the magnetic footprints of MMS. The earthward field-aligned Poynting flux of low-frequency waves reveals the energy transport from the DF toward the ionosphere. Meanwhile, small-scale and highly temporal ionospheric FACs suggest that the magnetotail shear Alfven waves may evolve into kinetic Alfven waves during the coupling processes. This finding implies that a very localized dynamic process (e.g., DFs in the terrestrial magnetotail) in the magnetosphere could couple the ionosphere with Alfven waves.
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We report deep-submicrometer gate-recessed and field-plated AlGaN-GaN HEMTs and their state-of-the-art continuous wave (CW) power performance measured at 30 GHz. The AlGaN-GaN HEMTs exhibit a CW power density of 5.7 W/mm with a po...
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We report deep-submicrometer gate-recessed and field-plated AlGaN-GaN HEMTs and their state-of-the-art continuous wave (CW) power performance measured at 30 GHz. The AlGaN-GaN HEMTs exhibit a CW power density of 5.7 W/mm with a power-added efficiency (PAE) of 45% and drain-efficiency of 58% at V{sub}(ds) = 20 V. At V{sub}(ds) = 28 V, the output power density is measured as high as 6.9 W/mm with both PAE and output power increasing with input power level. Compared to conventional T-gated AlGaN-GaN HEMTs, the output power density and PAE of gate-recessed AlGaN-GaN HFETs are improved greatly, along with the excellent pulsed IVs. We attribute the improvement to both a field-plating effect and a vertical separation of the gate plane from surface states.
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