Gate leakage current suppression and reliability improvement for ultra-low EOT Ge MOS devices by suitable HfAlO/HfON thickness and sintering temperature

Ultra-low effective oxide thickness (EOT) Ge MOS devices with different HfAlO/HfON stacks and sintering temperatures are investigated in this work. The suppression of gate leakage current and improvement of reliability properties can be achieved by either stacked gate dielectrics or a low sintering temperature. Especially, the qualities of the interface and high-k gate dielectric in Ge devices are significantly improved through a low sintering temperature. A 0.5 nm HfAlO/2.5 nm HfON gate stack and a sintering temperature at 350 °C are the suitable conditions to achieve low EOT, gate leakage, and good reliability for Ge MOS devices.     

Study on growth and photoluminescence of zinc telluride crystals synthesized by hydrothermal method

Zinc telluride powders were synthesized in sodium hydroxide solution by hydrothermal method by changing the growth temperature and time. The powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and micro-Raman spectroscopy, respectively. The results indicate that zinc telluride crystallizes in zinc blende structure and their sizes were increased with the increase in temperature and time, and oxygen easily is incorporated into zinc telluride crystals. The photoluminescence of the powders were investigated at room temperature. The photoluminescence spectra exhibit the emission peaks related to complex defects containing zinc vacancies and impurities and excitons bound to isoelectronic oxygen traps at about 556 and 703 nm, respectively. The growth of zinc telluride crystals and the relation of the photoluminescence with the growth conditions were analyzed.     

In vitro degradation resistance of glucose and L-cysteine-bioinspired Schiff-base anodic Ca–P coating on AZ31 magnesium alloy

A Schiff base (a compound containing a C=N bond) induced anodic Ca–P coating was prepared on AZ31 Mg alloy in a mixed solution of CaCl₂ and KH₂PO₄ at 60 °C in the presence of glucose and L-cysteine. The microstructure and chemical composition of the coatings were characterized using FE-SEM, FT-IR, XRD, and XPS. The in vitro degradation resistance of the coated samples was evaluated via potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and hydrogen evolution test. The experimental results show that the Ca–P_{Schiff base} coating is composed of CaHPO₄ (DCPA) and hydroxyapatite (HA), whereas HA is not present in the Ca–P coating. The Ca?P_{Schiff base} coating thickness is about 2 times that of Ca–P coating (Ca?P coating: (9.13±4.20) μm and Ca–P_{Schiff base}: (18.13±5.78) μm). The corrosion current density of the Ca–P_{Schiff base} coating is two orders of magnitude lower than that of the Ca–P coating. The formation mechanism of the Ca–P_{Schiff base} is proposed.     

Classification,summarization and perspective on modeling techniques for polymer electrolyte membrane fuel cell

Proton Exchange Membrane Fuel cell (PEMFC) model is helpful to understand the physical and chemical properties of the PEMFC and predict the performance of the PEMFC under different working conditions. Moreover, it can also provide essential references for evaluating new designs, new materials, and new control strategies. This paper specifically discusses PEMFC modeling at different scales, including single cell scale, stack scale and system scale. In addition, the main modeling approaches of the PEMFC are introduced in-depth, including mechanism approach, empirical approach, semi-empirical approach, equivalent circuit approach, and data-driven approach. The relationship between modeling approaches and different modeling scales is also discussed. At the same time, according to the different characteristics of the model, the modeling research in the last decade is summarized. On this basis, the development trend of the PEMFC modeling research is further analyzed by the statistical analysis method.     

高分子薄膜润滑在板料拉深中的应用研究与发展趋势

介绍了高分子薄膜润滑在板料拉深中的应用研究与发展趋势,分别从高分子摩擦润滑的机理、板料成形中高分子薄膜的润滑工艺以及高分子润滑材料的摩擦学研究3个方面概述了目前高分子薄膜润滑的研究及应用现状、高分子润滑剂的润滑特点,简述了高强度钢板拉深成形中存在的问题和高强度钢板成形时采用高分子薄膜进行润滑会获得良好的成形性能,并指出高分子薄膜润滑存在的问题和发展趋势。     

Electrochemical characterization of RuO2-Ta2O5/polyaniline composites as potential redox electrodes for supercapacitors and hydrogen evolution reaction

RuO₂-Ta₂O₅ electrode covered with polyaniline (PANI) was prepared by sintering and electrodeposition. X-ray photoelectron spectroscopy confirmed the presence of RuO₂-Ta₂O₅ and PANI and the strong interaction between RuO₂-Ta₂O₅ and PANI in the RuO₂-Ta₂O₅/PANI composite. The crystalline structure of RuO₂-Ta₂O₅/PANI was verified by XRD. SEM analysis revealed that the RuO₂-Ta₂O₅/PANI electrode had a nano-fibrous morphology with a crystal plane and some pores. The supercapacitive performance of RuO₂-Ta₂O₅/PANI was evaluated by cyclic voltammetry and charge-discharge chronopotentiometry. RuO₂-Ta₂O₅/PANI had a high specific capacitance (428 F/g), specific energy (26.7 Wh/kg at a discharge current density of 0.5 mA/cm²), and power density (2.4 kW/kg at a discharge current density of 4.0 mA/cm²). The attractive capacitive properties of RuO₂-Ta₂O₅/PANI may be attributed to the porous morphology of RuO₂-Ta₂O₅ covered with PANI. In addition, the as-prepared RuO₂-Ta₂O₅ and RuO₂-Ta₂O₅/PANI electrodes had Tafel slopes of −55.8 and −69.2 mV/dec, respectively, which make them potential H₂ evolution electrocatalysts.     

Review on health-conscious energy management strategies for fuel cell hybrid electric vehicles: Degradation models and strategies

Considering the overwhelming pressure on worldwide demand of fossil fuels and the climate change caused by air pollution, hybrid electric vehicles have seen a promising future thanks to the development of renewable energy sources. Among various kinds of energy sources that have been used in hybrid electric vehicles, lithium-ion battery and proton exchange membrane (PEM) fuel cell exist to be the most favorable ones owing to their high energy density and power density. However, the degradation issues of the energy sources tend to be neglected when designing the energy management strategies for the hybrid electric vehicles. Concerning existing literature, degradation modelling methods of lithium-ion batteries and PEM fuel cells are reviewed and the possibility of integrating them into health-conscious energy management is discussed. Besides, a variety of energy management strategies that have taken the influence of degradations into consideration are reviewed and classified. The contribution of this paper is to investigate the possibility of developing a health-conscious energy management strategy based on accurate estimation of degradation to improve the durability of the system.     

Effect of temperature,humidity and crystal directions on wear of rotary heads

In the advanced tape drive systems which achieve a higher recording density, the wear of rotary heads should be decreased to obtain a higher reproduced output signal by decreasing the ‘Gap depth’ of heads, keeping enough life time. By using the heads made by two kinds of crystal directions of Mn–Zn ferrite and metal evaporated tapes with DLC coating, temperature and humidity dependences of head wear are investigated. The wear rates of both crystal direction heads increase with the decrease in temperature. The wear rate of a (110) head increases very quickly at low temperature, compared with a (100) head. These temperature dependences of head wear are caused by the temperature dependence of the elastic modulus of the tape and the temperature dependence of the friction coefficient between the tape and the head.     

Electronic properties of BN nanocones under electric fields

The electronic properties of BN nanocones with 240° disclination under electric fields are investigated using first-principles calculations based on the density-functional theory. The cones are studied under the influence of electric fields, up to 1.13 V/Å, applied along the cone axis. The densities of states (DOS) of these BN nanocones show different patterns depending on the termination two atoms (BN, BB or NN) and the electric field strength. A decreasing of the gap is observed with increasing field. The field emission properties are very sensitive to the DOS and we show that the termination atoms, as well as the electric field, contribute to enhance the electron field emission.