雷电脉冲对导体平面窄缝隙穿透的时域分析

研究无限大导体平面任意形状窄缝隙对雷电脉冲的时域穿透特性。文中以窄缝隙内等效面磁流为未知量建立了时域微积分方程，寻求了一种稳定有效的数值求解方法，编程计算了穿透电场时域特性，并给出了分析结论。     

Adsorptive voltammetry of Hg(II) ions at a glassy carbon electrode coated with electropolymerized methyl-red film

The glassy carbon electrode coated with electropolymerized methyl-red film, 1.2 × 10⁻⁶ m in thickness, (PMRE) showed high sensitivity towards Hg(II) ions. PMREs were adopted to accumulate and detect Hg(II) ions in a pH 2.56 Britton–Robinson buffer solution. Cyclic voltammogram of the accumulated Hg species on PMREs exhibited an anodic wave at 0.64 V and a cathodic wave at 0.13 V, due to the oxidation of accumulated Hg species on PMREs and the reduction of Hg(II) ions in the solution, respectively. For this heterogeneous adsorption of Hg(II) ions onto PMREs, the maximum surface concentration, adsorption equilibrium, and Gibbs energy change were evaluated to be 5.12 × 10⁻⁶ mol m⁻², 3.7 × 10⁵ l mol⁻¹, and −30.1 kJ mol⁻¹, respectively. The anodic peak current at 0.64 V was linear with the concentration of Hg(II) ions in the range of 1.1 × 10⁻¹⁰ to 1.1 × 10⁻⁷ M with a detection limit of 4.4 × 10⁻¹¹ M. The proposed method was utilized successfully for the detection of Hg(II) ions in the lake water.     

数控伺服系统跟踪及轮廓误差分析

分析了数控加工中伺服系统跟踪误差和轮廓误差的计算方法,详细讨论了双轴数控加工中轴跟踪误差和轮廓误差之间的关系。指出了多轴加工中轮廓误差建模和误差控制方法的理论意义和应用价值。     

Revealing component synergy of Ni‒Fe/black phosphorous composites synthesized by self-designed electrochemical method for enhancing photoelectrocatalytic oxygen evolution reaction

Developing high-activity and low-cost catalysts is the key to eliminate the limitation of sluggish anodic oxygen evolution reaction (OER) during electrocatalytic overall water splitting. Herein, Ni‒Fe/black phosphorous (BP) composites are synthesized using a simple three-electrode system, where exfoliation of bulky BP and synthesis of NiFe composites are simultaneously achieved. Under light illumination, the optimized Ni‒Fe/BP composite exhibits excellent photoelectrocatalytic OER performance (e.g., the overpotential is 58 mV lower than a commercial RuO₂ electrocatalyst at a current density of 10 mA·cm⁻²). The electron transfer on this composite is proved to follow a Ni‒BP‒Fe pathway. The electronic structure of this Ni‒Fe/BP composite is effectively regulated, leading to optimized adsorption strength of the intermediate OH* and improved intrinsic activity for the OER. Together with active sites on the support, this Ni‒Fe/BP composite possesses abundant electrochemical active sites and a bug surface area for the OER. The introduction of light further accelerates the electrocatalytic OER. This work provides a novel and facile method to synthesize high-performance metal/BP composites as well as the approaches to reveal their OER mechanisms.     

Coking-resistant NbOx-Ni-Ce0.8Sm0.2O1.9 anode material for methanol-fueled solid oxide fuel cells

NbO_x is added in Ni-Ce_0.8Sm_0.2O_1.9 by impregnation as an anode material for solid oxide fuel cells fed with methanol. Nb (IV) and Nb (V) exist in the reduced anode. The addition of Nb reduces the binding energy of Ni. The catalytic activity of the anode and the performance of the single cell both increase with the increase of Nb. At 700 °C, the cell with 5NbO_x-Ni-Ce_0.8Sm_0.2O_1.9 anode and Ce_0.8Sm_0.2O_1.9-carbonate electrolyte shows a output power density of 687 mW cm^?2. Meanwhile, water produced in the anode is absorbed by NbO_x and forms surface hydroxyl groups, which facilitates the removal of carbon. The addition of NbO_x decreases the amount of deposited carbon in the humidified methanol atmosphere significantly, and an improved stability of the single cell is achieved.     

[BMIm]BF4离子液体修饰的铜纳米粒子的制备

在[BMIm]BF4离子液体的修饰下,用抗坏血酸还原CuCl2 溶液制备出了铜纳米粒子。Cu2+浓度对铜纳米粒子的尺寸有着非常明显的影响。当Cu2+浓度小于2×10-2mol/L时,所制备的铜纳米粒子的直径小于10nm。还原反应的pH值和温度对铜纳米离子的尺寸没有明显影响。     

Interface properties of cytochrome c on a nano-textured diamond surface

The electron transfer process and the peroxidase activity of native and denatured cytochrome c were investigated on OH-terminated diamond nano-textured surfaces. The nano-textured surfaces with geometrical properties of typical protein dimensions were fabricated by a top-down technology, where diamond nanoparticles are used as etching masks. The cyclic voltammogram of native cytochrome c shows an adsorption-controlled, reversible electron transfer process of the heme redox center, which was not detected for denatured cytochrome c. Native cytochrome c denatures in the presence of hydrogen peroxide. Higher peroxidase activity was found on the denatured cytochrome c than on native cytochrome c. The apparent Michaelis-Menten constants K_m for denatured cytochrome c and the native cytochrome c were determined to be 0.08 and 0.23 mM, respectively.