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Evidence for the Formation of Quasi-Bound-State in an Asymmetrical Quantum Point Contact
Features below the first conductance plateau in ballistic quantum point
contacts (QPCs) are often ascribed to electron interaction and spin effects
within the single mode limit. In QPCs with a highly asymmetric geometry, we
observe sharp resonance peaks when the point contacts are gated to the single
mode regime, and surprisingly, under certain gating conditions, a complete
destruction of the 2e^2/h, first quantum plateau. The temperature evolution of
the resonances suggest non-Fermi liquid behavior, while the overall nonlinear
characterizations reveal features reminiscent of the 0.7 effect. We attribute
these unusual behaviors to the formation of a quasi bound state, which is
stabilized by a momentum-mismatch accentuated by asymmetry.Comment: 5 pages, 5 figure
A Comparative Study on Regularization Strategies for Embedding-based Neural Networks
This paper aims to compare different regularization strategies to address a
common phenomenon, severe overfitting, in embedding-based neural networks for
NLP. We chose two widely studied neural models and tasks as our testbed. We
tried several frequently applied or newly proposed regularization strategies,
including penalizing weights (embeddings excluded), penalizing embeddings,
re-embedding words, and dropout. We also emphasized on incremental
hyperparameter tuning, and combining different regularizations. The results
provide a picture on tuning hyperparameters for neural NLP models.Comment: EMNLP '1
Improvement of corrosion resistance in NaOH solution and glass forming ability of as-cast Mg-based bulk metallic glasses by microalloying
The influences of the addition of Ag on the glass forming ability (GFA) and corrosion behavior were investigated in the Mg-Ni-based alloy system by X-ray diffraction (XRD) and electrochemical polarization in 0.1 mol/L NaOH solution. Results shows that the GFA of the Mg-Ni-based BMGs can be improved dramatically by the addition of an appropriate amount of Ag; and the addition element Ag can improve the corrosion resistance of Mg-Ni-based bulk metallic glass. The large difference in atomic size and large negative mixing enthalpy in alloy system can contribute to the high GFA. The addition element Ag improves the forming speed and the stability of the passive film, which is helpful to decrease the passivation current density and to improve the corrosion resistance of Mg-Ni-based bulk metallic glass
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