对流扩散方程特征线三角元法的一致估计

利用三角形线性元的积分恒等式,给出了二维非定常对流占优扩散方程的特征线有限元解和真解的一致最优估计,并利用插值后处理算子,得到了有限元解梯度的一致超收敛估计,即只与初值和右端项有关,而与ε无关

Electrochemical and In Situ FTIR Studies of Adsorption and Oxidation of Dimethyl Ether on Platinum Electrode

运用电化学循环伏安法(CV)和原位傅立叶变换红外(FTIR)反射光谱,研究了不同pH值溶液中二甲醚(DME)在Pt电极上的解离吸附和氧化过程.稳态CV结果给出,在0.1mol·L-1H2SO4溶液中,当电位处于0.05-0.35V(vsRHE)区间,约70%的Pt表面位被DME的解离吸附产物占据.DME电氧化反应的活性随pH值增加而下降,在0.1mol·L-1NaOH溶液中,氢的吸脱附几乎不受抑制且观察不到明显的氧化电流,表明DME醚键上氧原子的质子化是其发生解离吸附和氧化的必要条件.原位FTIR光谱研究给出DME解离吸附和氧化过程的分子水平信息,指出DME在低电位区间解离生成线型吸附态CO(COL)毒性中间体.当电位高于0.55V(vsRHE)时,COL开始氧化为CO2;在0.75-1.00V(vsRHE)的电位区间则可同时发生经活性中间体(HCOOH)的氧化过程.Dissociative adsorption and electrooxidation of dimethyl ether (DME) on a platinum electrode in different pH solutions were studied using cyclic voltammetry (CV) and in situ FTIR reflection spectroscopy. The coverage of the dissociative adsorbed species was measured about 70% from hydrogen adsorption-desorption region (0.05-0.35 V(vs RHE)) of steady-state voltammogram recorded in 0.1 mol·L-1 H2SO4 solution. It was found that the electrochemical reactivity of DME was pH dependent, i.e., the larger the pH value was, the less the reactivity of DME would be. No perceptible reactivity of DME in 0.1 mol·L-1 NaOH solution could be detected. It was revealed that the protonation of the oxygen atom in the C-O-C bond played a key role in the electrooxidation of DME. In situ FTIR spectroscopic results illustrated that linearly bonded CO (COL) species determined at low potential region were derived from the dissociative adsorption of DME and behaved as 'poisoning' intermediate. The COL species could be oxidized to CO2 at potential higher than 0.55 V (vs RHE), and in the potential range from 0.75 to 1.00 V (vs RHE) DME was oxidized simultaneously via HCOOH species that were identified as the reactive intermediates.国家自然科学基金(20433060,20673091)资助项

对流扩散方程三角形有限元解的一致估计

利用三角形线性元的积分恒等式,给出了二维非定常对流扩散方程的半离散有限元解和真解的一致最优误差估计,即误差与ε无关,而仅与右端f和初值u_0有关

一种人工湿地堵塞监测装置

本实用新型公开了一种人工湿地堵塞监测装置。装置内上层筒、内中层筒、内下层筒底部分别固定一块固定透水板。内中层筒对齐内下层筒并置于其上，内上层筒对齐内中层筒并置于其上，内上层筒、内中层筒、内下层筒组成内筒。内筒顶部和底部分别有不锈钢片连接不锈钢螺纹棒固定夹紧内筒，内下层筒由不锈钢片中心的固定螺母将底部和不锈钢片固定。上部的不锈钢片两端用固定螺母与不锈钢螺纹棒连接，中心有吊环螺母，吊环中心穿绳或插入木棒作为提柄。使用时，将内筒装满基质，连接好后置于外筒中。一种监测装置在人工湿地堵塞中的应用，可方便实时监测人工湿地，调整湿地运行条件，便捷回收增效剂，延长人工湿地使用寿命。</p

Electrochemical and In Situ FTIR Studies of Adsorption and Oxidation of Dimethyl Ether on Platinum Electrode

Dissociative adsorption and electrooxidation of dimethyl ether (DME) on a platinum electrode in different pH solutions were studied using cyclic voltammetry (CV) and in situ FTIR reflection spectroscopy. The coverage of the dissociative adsorbed species was measured about 70% from hydrogen adsorption-desorption region (0.05-0.35 V(vs RHE)) of steady-state voltammogram recorded in 0.1 mol center dot L-1 H2SO4 solution. It was found that the electrochemical reactivity of DME was pH dependent, i.e., the larger the pH value was, the less the reactivity of DME would be. No perceptible reactivity of DME in 0.1 mol center dot L-1 NaOH solution could be detected. It was revealed that the protonation of the oxygen atom in the C-O-C bond played a key role in the electrooxidation of DME. In situ FTIR spectroscopic results illustrated that linearly bonded CO (COL) species determined at low potential region were derived from the dissociative adsorption of DME and behaved as 'poisoning' intermediate. The COL species could be oxidized to CO2 at potential higher than 0.55 V (vs RHE), and in the potential range from 0.75 to 1.00 V (vs RHE) DME was oxidized simultaneously via HCOOH species that were identified as the reactive intermediates