204 research outputs found

    Interaction Between Hot Carrier Aging and PBTI Degradation in nMOSFETs: Characterization, Modelling and Lifetime Prediction

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    Modelling of the interaction between Hot Carrier Aging (HCA) and Positive Bias Temperature Instability (PBTI) has been considered as one of the main challenges in nanoscale CMOS circuit design. Previous works were mainly based on separate HCA and PBTI instead of Interacted HCA-PBTI Degradation (IHPD). The key advance of this work is to develop a methodology that enables accurate modelling of IHPD through understanding the charging/discharging and generation kinetics of different types of defects during the interaction between HCA and PBTI. It is found that degradation during alternating HCA and PBTI stress cannot be modelled by independent HCI/PBTI. Different stress sequence, i.e. HCA-PBTI-HCA and PBTI-HCA-PBTI, lead to completely different degradation kinetics. Based on the Cyclic Anti-neutralization Model (CAM), for the first time, IHPD has been accurately modelled for both short and long channel devices. Complex degradation mechanisms and kinetics can be well explained by our model. Our results show that device lifetime can be underestimated by one decade without considering interaction

    Simulation of reference crop evapotransiration in a plastic solar green house using a simplified energy balance approach

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    Proceedings of International conference on Agricultural and Biological Sciences (ABS 2015) held in Beijing, China on July 25-27, 2015With larger planting areas being used in greenhouses, evaluating crop evapotranspiration in a greenhouse has garnered greater attention. Currently, calculating the reference crop evapotranspiration for a greenhouse crop through using the Penman-Monteith formula recommended by FAO is difficult because the wind speed in a greenhouse is approximate zero. In order to calculate reference crop evapotranspiration in a greenhouse by the Penman-Monteith modified formula, a simplified model for calculating reference crop evapotranspiration in a greenhouse was proposed based on the energy balance equation, which was the correlative function between reference crop evapotranspiration and radiation and temperature. The model's parameters were obtained through meteorological data taken from the inside of a greenhouse in 2011. Then, the model was validated by using meteorological data within the greenhouse in 2012, and the fitted value of the model agreed with the calculated value of the formulas with a determination coefficient (R2) of 0.9554. This model is an easy means of calculating the reference crop evapotranspiration in a greenhouse because less meteorological factors are needed. Furthermore, the model provides a theoretical basis for crop irrigation in greenhouses

    Epitaxial Catalyst-Free Growth of InN Nanorods onc-Plane Sapphire

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    We report observation of catalyst-free hydride vapor phase epitaxy growth of InN nanorods. Characterization of the nanorods with transmission electron microscopy, and X-ray diffraction show that the nanorods are stoichiometric 2H–InN single crystals growing in the [0001] orientation. The InN rods are uniform, showing very little variation in both diameter and length. Surprisingly, the rods show clear epitaxial relations with thec-plane sapphire substrate, despite about 29% of lattice mismatch. Comparing catalyst-free with Ni-catalyzed growth, the only difference observed is in the density of nucleation sites, suggesting that Ni does not work like the typical vapor–liquid–solid catalyst, but rather functions as a nucleation promoter by catalyzing the decomposition of ammonia. No conclusive photoluminescence was observed from single nanorods, while integrating over a large area showed weak wide emissions centered at 0.78 and at 1.9 eV

    EELS analysis of manganese valence states in rare-earth manganites (La1-xYx)(0.5)(Ca1-ySry)(0.5)MnO3

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    Using the white line intensities, electron energy-loss spectroscopy in a transmission electron microscope has been applied to characterizing the valence state of manganese in the system (La1−xYx)0.5(Ca1−ySry)0.5MnO3 at room temperature and lower temperature (93 K), respectively. The results show that the valence state of manganese keeps consistent (close to 3.5) in this system at room temperature and lower temperature

    Independent unfair-profits management organisation for power transmission system operations

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    Market driven mechanism for transmission system operation and management is studied. An example is given to show that transmission congestion may be abused by transmission system operators to obtain unfair profits. That's the economic benefits of transmission system operators and the economic benefits of generators and electricity users are not always consistent with each other, which discourages the operators to operate the system efficiently. Therefore, a mechanism is proposed for transmission management commercialization with operators' profits being consistent with social benefits. An independent unfair-profits management organization should be set up to deprive transmission system operators of all unfair profits, while the operators both manage power exchange and operate transmission system. The theory impels transmission system operators manage and operate transmission system efficiently by increasing the operators' own profits. It'll be the foundation for further developing market competition of transmission management

    Effect of A-site cation size mismatch on charge ordering behavior in (La1-xYx)(0.5)(Ca1-ySry)(0.5)MnO3

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    Electron energy-loss spectroscopy (EELS) has been used to determine the valence state of manganese for all the samples at low temperature (93 K). EELS results indicate that the valence state of manganese keeps constant (∼3.5) for all the samples. The effects of the A-site cation size mismatch on the charge ordering (CO) behaviors in the manganites (La1−xYx)0.5(Ca1−ySry)0.5MnO3(La1−xYx)0.5(Ca1−ySry)0.5MnO3 are studied by transmission electron microscopy (TEM). TEM images show that the size mismatch and disorder of A-site cations have a suppression effect on the CO transition. The schematic models are proposed for the incommensurate CO modulation in the samples with size mismatch σ2⩽0.003.σ2⩽0.003. The disappearance of the CO transition in the sample with the largest mismatch (σ2=0.005)(σ2=0.005) is explained by the random arrangements of Mn3+Mn3+ and Mn4+Mn4+ ions
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