Evaluation of stability and robustness of poly-Si resistors with different dopant concentrations

The stability and robustness of lightly and highly doped poly-Si resistors were evaluated. These resistors exhibited distinct electrical resistance properties and temperature dependences, which can be explained through the grain and grain boundary conduction mechanisms. The resistance shift saturated under the low current stress condition, but continued to increase under the high current stress condition. A novel carrier trapping density model was proposed to explain this behavior. A generalized free energy model that considered stress temperature and stress current dependences was proposed to account for the stability lifetime of a poly-Si resistor based on the resistance shift criterion. Robustness evaluation with transmission line pulse test revealed that the breakdown current exhibited a pulse width dependence which was further explained by a thermal- conduction energy model.

A Thermodynamic model for the subsolidus evolution and melting of peridotite

We present a structural update to the thermodynamic model for calculating peridotite phase relations and melt compositions at 0.01 to 60 kbar and from 600 °C to the peridotite liquidus in the system K2O–Na2O–CaO–FeO–MgO–Al2O3–SiO2–TiO2–Fe2O3–Cr2O3 (KNCFMASTOCr), based on the model of Holland et al., 2018 [Melting of Peridotites through to Granites: A Simple Thermodynamic Model in the System KNCFMASHTOCr. Journal of Petrology 59, 881–900]. The new model is better able to predict the phase relations and melting of ultramafic rocks, in particular the abundance of orthopyroxene in the residue and the concentration of silica in the melt. In addition, improvements in modelling Cr-spinels mean that the model is now able to reproduce Cr-content of garnet and spinel above and below the solidus without modification to the knorringite free energy. Model calculations indicate that, for peridotite composition KR4003, the spinel to garnet transition intersects the solidus at 22.1–24.8 kbar and orthopyroxene disappears from the solidus at 29.1 kbar. Below the solidus, the model is able to reproduce the abundances and compositions of phases in experimental studies and natural samples spanning a range of compositions, allowing it to be used for investigating subsolidus equilibration during mantle cooling and pressurisation/decompression. The liquid model provides a good fit to experimental data and is able to replicate the position of the solidus and the composition of both melt and residue at and above the solidus for a range of peridotite compositions. The model may therefore be used to investigate fractional mantle melting and basalt generation in modern geodynamic regimes, and also to explore equilibrium mantle melting in the early Earth. The model can also be used to explore liquid and residue compositions for melting of non-pyrolitic mantle, for which there is a paucity of experimental data. We demonstrate the scope of the model using two case studies investigating the subsolidus evolution and melting of a silica-rich cratonic peridotite from the Kaapvaal craton.

Calculation of Dynamical Phase Diagram in U-Zr Binary System Under Irradiation

By taking into account the ballistic mixing caused by recoil implantation and cascade collision, a model that describing effective free energy for alloys under irradiation from the perspective of diffusion equilibrium was used to study the effect of irradiation-induced defects on phase stability in U-Zr binary system. Based on the effective free energy model and the thermodynamic model, dynamical phase diagrams of U-Zr alloy under different irradiation intensities were calculated, and the differences between the dynamical phase diagram and thermodynamic equilibrium phase diagram (TEPD) were discussed. The obtained results indicate that, under irradiation, the high-temperature stable γ(U, Zr) phase can be stabilized resulting in two invariant reactions at low temperature, which could be ascribed to the domination of irradiation-induced ballistic mixing.

Size Effect on Structure and Stiffness of Viral DNA during Temperature Variation

Structure and stiffness of nucleic acids are closely related to viral infectivity. The article is aimed to clarify a recent controversy on structure variation of viral DNA in temperature-dependent experiments. A multi-scale correlation between microscopic structure of viral DNA and its bulk stiffness is formulated by presenting a two-zone mesoscopic free energy model. Results reveal that the increasing temperature promotes DNA structure transformation from order to disorder, and leads to size effect on temperature-dependency of stiffness and structure of viral DNA.

Hydrogen Atom Transfer Reaction Free Energy as a Predictor of Abiotic Nitroaromatic Reduction Rate Constants: A Comprehensive Analysis

<div>A linear free energy model is presented that predicts the second order rate constant for the abiotic reduction of nitroaromatic compounds (NACs). For this situation previously presented models use the one electron reduction potential of the NAC reaction. If such value is not available, it has been has been proposed that it could be computed directly or estimated from the electron affinity (EA). The model proposed herein uses the Gibbs free energy of the hydrogen atom transfer (HAT) as the parameter in the linear free energy model. Both models employ quantum chemical computations for the required thermodynamic parameters. The available and proposed models are compared using second order rate constants obtained from five investigations reported in the literature in which a variety of NACs were exposed to a variety of reductants. A comprehensive analysis utilizing all the NACs and reductants demonstrate that the computed hydrogen atom transfer model and the experimental one electron reduction potential model have similar root mean square errors and residual error probability distributions. In contrast, the model using the computed electron affinity has a more variable residual error distribution with a significant number of outliers. The results suggest that a linear free energy model utilizing computed hydrogen transfer reaction free energy produces a more reliable prediction of the NAC abiotic reduction second order rate constant than previously available methods. The advantages of the proposed hydrogen atom transfer model and its mechanistic implications are discussed as well.</div>