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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Organic thin film devices that included an organic thin film subjected to a selected dose of a selected energy of ions exhibited a stabilized mobility (.mu.) and threshold voltage (VT), a decrease in contact resistance R.sub.C, and an extended operational lifetime that did not degrade after 2000 hours of operation in the air.
A polymer-hybrid electro-optic device is fabricated by providing a semiconductor substrate, depositing a metal electrode layer on the semiconductor substrate, depositing a dielectric barrier core layer within a gap of the metal electrode layer, patterning a polymer layer to cover the dielectric barrier core layer and partially covering the metal electrode layer, infiltrating the polymer layer with an inorganic component to form a hybrid oxide-polymer layer, and removing excess inorganic component from the semiconductor substrate and metal electrode layer.
A semiconductor power device including a base plate; an input lead; an output lead; a field effect transistor (FET) power die disposed over the base plate, wherein the FET power die includes a set of source fingers, a set of drain fingers, and a set of gate fingers disposed directly over an active region, wherein the gate fingers are configured to receive an input signal from the input lead, and wherein the FET power die is configured to process the input signal to generate an output signal at the drain fingers for routing to the output lead; and electrical conductors (wirebonds or ribbons) bonded to the source and/or drain directly over the active region of the FET power die. The electrical conductors produce additional thermal paths between the active region and the base plate for thermal management of the FET power die.
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A class of wide bandgap host materials is introduced as an alternative to carbazole-based hosts to enhance the efficiency and transport properties of organic light emitting diodes (OLEDs). We have synthesized and investigate the photophysical and electrochemical properties of a series of phenanthrene derivatives incorporating fused triazole or imidazole rings. Here, the resulting phenanthro[9,10-d]triazoles and phenanthro[9,10-d]imidazoles are suitable host materials for blue phosphors due to their high triplet energies and conductivities. Incorporation of bulky substituent groups leads to retention of the high triplet energies in the solid state. The most promising materials are incorporated in blue phosphorescent OLEDs that achieve external quantum efficiencies >20%.
The model, including shielding effects of high-Z dust grain ablation in tokamak edge plasma, is presented. In a contrast to shielding models developed for pellets ablation in a hot plasma core, this model deals with the dust grain ablation in relatively cold edge plasma. Using some simplifications, a closed set of equations determining the grain ablation rate Γ is derived and analyzed both analytically and numerically. The scaling law for Γ versus grain radius and ambient plasma parameters is obtained and confirmed by the results of numerical solutions. The results obtained are compared with both dust grain models containing no shielding effects and the pellet ablation models.
A new high pedestal regime (“Super H-mode”) has been predicted and accessed on DIII-D. Super H-mode was first achieved on DIII-D using a quiescent H-mode edge, enabling a smooth trajectory through pedestal parameter space. By exploiting Super H-mode, it has been possible to access high pedestal pressures at high normalized densities. While elimination of Edge localized modes (ELMs) is beneficial for Super H-mode, it may not be a requirement, as recent experiments have maintained high pedestals with ELMs triggered by lithium granule injection. Simulations using TGLF for core transport and the EPED model for the pedestal find that ITER can benefit from the improved performance associated with Super H-mode, with increased values of fusion power and gain possible. Similar studies demonstrate that the Super H-mode pedestal can be advantageous for a steady-state power plant, by providing a path to increasing the bootstrap current while simultaneously reducing the demands on the core physics performance.
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