Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of N...Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of Na2SO3 into the solution can accelerate anodic dissolution of gold. The factors affecting selective dissolution of gold in the alkaline thiourea solution by electrolysis have been studied, and the optimum condition was obtained. In 0.1 mol/L thiourea solution of pH 12. 5 containing 0. 5 mol/L Na2SO3 and 2. 5% acetone, at the potential of 0. 34 V vs NHE, at the temperature of 323 K, the dissolved mass of gold anode with the exposed area of 1. 0 cm2 reached more than 300 mg·dm-3 within 30 min, and other metals such as silver, copper, nickel and iron could hardly dissolve.展开更多
For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-p...For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-plastic finite element(FE) model of NC bending process was established under ABAQUS/Explicit platform, and its reliability was validated by the experiment. Then, numerical study on bending deformation behaviors under different frictions between tube and various dies was explored from multiple aspects such as wrinkling, wall thickness change and cross section deformation. The results show that the large friction of wiper die-tube reduces the wrinkling wave ratio η and cross section deformation degree ΔD and increases the wall thinning degree Δt. The large friction of mandrel-tube causes large η, Δt and ΔD, and the onset of wrinkling near clamp die. The large friction of pressure die-tube reduces Δt and ΔD, and the friction on this interface has little effect on η. The large friction of bending die-tube reduces η and ΔD, and the friction on this interface has little effect on Δt. The reasonable friction coefficients on wiper die-tube, mandrel-tube, pressure die-tube and bending die-tube of 21-6-9(0Cr21Ni6Mn9N) stainless steel tube in NC bending are 0.05-0.15, 0.05-0.15, 0.25-0.35 and 0.25-0.35, respectively. The results can provide a guideline for applying the friction conditions to establish the robust bending environment for stable and precise bending deformation of tube bending.展开更多
随着向新型能源体系的转型加速,亟待开展对多元负荷用户的复杂用能特性分析的深入研究。提出了一种综合考量电、冷、热多元负荷耦合特性的用户用能特性标签库构建技术及用户画像方法。首先运用快速相关性滤波算法剔除高冗余低相关特征,...随着向新型能源体系的转型加速,亟待开展对多元负荷用户的复杂用能特性分析的深入研究。提出了一种综合考量电、冷、热多元负荷耦合特性的用户用能特性标签库构建技术及用户画像方法。首先运用快速相关性滤波算法剔除高冗余低相关特征,并通过随机森林和递归式特征消除算法精选出具有强区分能力的用能特征。在聚类阶段,改进的自适应三支密度峰值聚类算法(three-way adaptive density peak clustering,3W-ADPC)通过结合自适应近邻搜索和三支聚类算法提升负荷聚类效果。实证结果表明,所提方法具备在计算效率和聚类精度上的双重优势,能够精准揭示多元负荷用户综合用能特性和深层次信息,证实所提方法在多元负荷用户行为研究中的实用价值。展开更多
文摘Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of Na2SO3 into the solution can accelerate anodic dissolution of gold. The factors affecting selective dissolution of gold in the alkaline thiourea solution by electrolysis have been studied, and the optimum condition was obtained. In 0.1 mol/L thiourea solution of pH 12. 5 containing 0. 5 mol/L Na2SO3 and 2. 5% acetone, at the potential of 0. 34 V vs NHE, at the temperature of 323 K, the dissolved mass of gold anode with the exposed area of 1. 0 cm2 reached more than 300 mg·dm-3 within 30 min, and other metals such as silver, copper, nickel and iron could hardly dissolve.
基金Project(51164030)supported by the National Natural Science Foundation of China
文摘For contact dominated numerical control(NC) bending process of tube, the effect of friction on bending deformation behaviors should be focused on to achieve precision bending forming. A three dimensional(3D) elastic-plastic finite element(FE) model of NC bending process was established under ABAQUS/Explicit platform, and its reliability was validated by the experiment. Then, numerical study on bending deformation behaviors under different frictions between tube and various dies was explored from multiple aspects such as wrinkling, wall thickness change and cross section deformation. The results show that the large friction of wiper die-tube reduces the wrinkling wave ratio η and cross section deformation degree ΔD and increases the wall thinning degree Δt. The large friction of mandrel-tube causes large η, Δt and ΔD, and the onset of wrinkling near clamp die. The large friction of pressure die-tube reduces Δt and ΔD, and the friction on this interface has little effect on η. The large friction of bending die-tube reduces η and ΔD, and the friction on this interface has little effect on Δt. The reasonable friction coefficients on wiper die-tube, mandrel-tube, pressure die-tube and bending die-tube of 21-6-9(0Cr21Ni6Mn9N) stainless steel tube in NC bending are 0.05-0.15, 0.05-0.15, 0.25-0.35 and 0.25-0.35, respectively. The results can provide a guideline for applying the friction conditions to establish the robust bending environment for stable and precise bending deformation of tube bending.
文摘随着向新型能源体系的转型加速,亟待开展对多元负荷用户的复杂用能特性分析的深入研究。提出了一种综合考量电、冷、热多元负荷耦合特性的用户用能特性标签库构建技术及用户画像方法。首先运用快速相关性滤波算法剔除高冗余低相关特征,并通过随机森林和递归式特征消除算法精选出具有强区分能力的用能特征。在聚类阶段,改进的自适应三支密度峰值聚类算法(three-way adaptive density peak clustering,3W-ADPC)通过结合自适应近邻搜索和三支聚类算法提升负荷聚类效果。实证结果表明,所提方法具备在计算效率和聚类精度上的双重优势,能够精准揭示多元负荷用户综合用能特性和深层次信息,证实所提方法在多元负荷用户行为研究中的实用价值。
