With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that mag...With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that magnetic flux density and electromagnetic body force in the aluminum melt are greatly increased when the external part of mould is made from A3 steel. A low-frequency electromagnetic casting 6063 aluminum alloy experiment was conducted in the laboratory with the current value of 120 A and frequency value of 15 Hz. The experiment showed that the microstructure and surface quality of ingots with mould outer part made from A3 steel under low-frequency electromagnetic field are better than that of ingots with mould outer part made from austenitic stainless steel. The surface of the ingots with mould outer part made from A3 steel is smooth and free from exudations and cold shut defects. The as-cast microstructure consists of fine, uniformly distributed equiaxed grains.展开更多
锂电池的荷电状态(state of charge, SOC)作为锂电池的重要参数之一,其估算精度对锂电池的管理有很大影响。扩展卡尔曼滤波算法作为常用的SOC估算方法,忽略了噪声变化对SOC估算的影响,在运用时会出现噪声误差累积的情况。自适应扩展卡...锂电池的荷电状态(state of charge, SOC)作为锂电池的重要参数之一,其估算精度对锂电池的管理有很大影响。扩展卡尔曼滤波算法作为常用的SOC估算方法,忽略了噪声变化对SOC估算的影响,在运用时会出现噪声误差累积的情况。自适应扩展卡尔曼滤波算法能对扩展卡尔曼滤波算法估算SOC时的噪声进行修正。实验结果表明,该方法能有效提高SOC估算精度。在动态应力测试工况下,估算精度提高2%;在北京公交纯电动客车动态应力测试工况下,估算精度提高0.39%。该方法能够提高实际应用中的SOC估算精度,从而可以提高锂电池的管理效率。展开更多
作为黄海的代表性冷温性鱼类,大头鳕(Gadus macrocephalus)的资源量近年逐渐上升趋势,其中幼鱼所占比重较大,种群丰度及补充都受到黄海冷水团的影响,作为2龄性成熟鱼种,探究其当年生和非当年生幼鱼分布和生长的季节变化及与黄海冷水团...作为黄海的代表性冷温性鱼类,大头鳕(Gadus macrocephalus)的资源量近年逐渐上升趋势,其中幼鱼所占比重较大,种群丰度及补充都受到黄海冷水团的影响,作为2龄性成熟鱼种,探究其当年生和非当年生幼鱼分布和生长的季节变化及与黄海冷水团的关系对了解大头鳕的资源变动有重要意义。本研究基于2016年10月、2017年5和8月的调查结果,分析了黄海冷水团存在时期的海洋环境特征与大头鳕幼鱼分布及生长特征的关系。研究显示,春季,幼鱼主要分布于青海渔场、石岛渔场和连青石渔场,非当年生幼鱼和当年生幼鱼随栖息地水深分别呈东西两区块分布。夏季,幼鱼主要位于122.00°E以东、底温低于10℃的黄海中部较深海域,有少部分分布于黄海北部,这与黄海冷水团强盛时期南北低温中心的位置有关。秋季,黄海北部大头鳕幼鱼的渔获量明显减少,仅在石岛渔场和连青石渔场大头鳕的种群密度仍较高。广义相加模型(Generalized Additive Models,GAM)分析结果显示,温度和盐度对大头鳕幼鱼的资源丰度指数(单位捕捞努力量渔获量(Catch Per Unit Effort,CPUE))有显著影响,当栖息地水域盐度在31.90和32.80附近,底温在8.5℃左右时,大头鳕幼鱼的CPUE较高。体长-体重关系显示,春季,幼鱼呈负异速生长,夏秋季呈正异速生长,黄海冷水团强盛时期较高的有机质含量及初级生产力造成的丰富饵料可能是导致大头鳕夏秋季b值较高的原因,因此黄海冷水团的季节变化对大头鳕的分布和生长均有显著影响。展开更多
基金The project (G199906490501) was supported by the National Key Fundamental Research and Development Program of China
文摘With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that magnetic flux density and electromagnetic body force in the aluminum melt are greatly increased when the external part of mould is made from A3 steel. A low-frequency electromagnetic casting 6063 aluminum alloy experiment was conducted in the laboratory with the current value of 120 A and frequency value of 15 Hz. The experiment showed that the microstructure and surface quality of ingots with mould outer part made from A3 steel under low-frequency electromagnetic field are better than that of ingots with mould outer part made from austenitic stainless steel. The surface of the ingots with mould outer part made from A3 steel is smooth and free from exudations and cold shut defects. The as-cast microstructure consists of fine, uniformly distributed equiaxed grains.
文摘锂电池的荷电状态(state of charge, SOC)作为锂电池的重要参数之一,其估算精度对锂电池的管理有很大影响。扩展卡尔曼滤波算法作为常用的SOC估算方法,忽略了噪声变化对SOC估算的影响,在运用时会出现噪声误差累积的情况。自适应扩展卡尔曼滤波算法能对扩展卡尔曼滤波算法估算SOC时的噪声进行修正。实验结果表明,该方法能有效提高SOC估算精度。在动态应力测试工况下,估算精度提高2%;在北京公交纯电动客车动态应力测试工况下,估算精度提高0.39%。该方法能够提高实际应用中的SOC估算精度,从而可以提高锂电池的管理效率。
文摘作为黄海的代表性冷温性鱼类,大头鳕(Gadus macrocephalus)的资源量近年逐渐上升趋势,其中幼鱼所占比重较大,种群丰度及补充都受到黄海冷水团的影响,作为2龄性成熟鱼种,探究其当年生和非当年生幼鱼分布和生长的季节变化及与黄海冷水团的关系对了解大头鳕的资源变动有重要意义。本研究基于2016年10月、2017年5和8月的调查结果,分析了黄海冷水团存在时期的海洋环境特征与大头鳕幼鱼分布及生长特征的关系。研究显示,春季,幼鱼主要分布于青海渔场、石岛渔场和连青石渔场,非当年生幼鱼和当年生幼鱼随栖息地水深分别呈东西两区块分布。夏季,幼鱼主要位于122.00°E以东、底温低于10℃的黄海中部较深海域,有少部分分布于黄海北部,这与黄海冷水团强盛时期南北低温中心的位置有关。秋季,黄海北部大头鳕幼鱼的渔获量明显减少,仅在石岛渔场和连青石渔场大头鳕的种群密度仍较高。广义相加模型(Generalized Additive Models,GAM)分析结果显示,温度和盐度对大头鳕幼鱼的资源丰度指数(单位捕捞努力量渔获量(Catch Per Unit Effort,CPUE))有显著影响,当栖息地水域盐度在31.90和32.80附近,底温在8.5℃左右时,大头鳕幼鱼的CPUE较高。体长-体重关系显示,春季,幼鱼呈负异速生长,夏秋季呈正异速生长,黄海冷水团强盛时期较高的有机质含量及初级生产力造成的丰富饵料可能是导致大头鳕夏秋季b值较高的原因,因此黄海冷水团的季节变化对大头鳕的分布和生长均有显著影响。
基金Projects(51775480,51305385)supported by the National Natural Science Foundation of ChinaProject(E2018203143)supported by the Natural Science Foundation of Hebei Province,China
