以“竹藤种质资源数据库”中126个竹种为基础数据,应用K均值聚类算法(K-means算法)、小批量K均值聚类算法(Mini Batch K means算法)、凝聚层次聚类算法,依据竹种酸不溶木质素、苯醇提取物、综纤维素、基本密度、纤维长度、纤维双壁厚、...以“竹藤种质资源数据库”中126个竹种为基础数据,应用K均值聚类算法(K-means算法)、小批量K均值聚类算法(Mini Batch K means算法)、凝聚层次聚类算法,依据竹种酸不溶木质素、苯醇提取物、综纤维素、基本密度、纤维长度、纤维双壁厚、纤维壁腔比7个特征对竹种筛选分级,遴选优良造纸竹种,分析聚类算法对竹藤种质资源的聚类有效性。结果表明:K均值聚类算法具有最高的卡林斯其-哈瑞本斯(Calinski_Harabaz(CH))指标值(63.568),聚类效果最好,126个竹种分为3级。其中:Ⅰ级造纸竹种,包含糯竹、空竹等51个竹种,适合制作高级纸张;Ⅱ级造纸竹种,包括毛竹、思劳竹等62个竹种,适合在排污能力强的造纸厂做纸浆造纸原料。K均值聚类算法是竹种造纸适应性分析的高效可靠的方法,具有较好的应用前景。展开更多
The electrochemical stability of lithium-ion batteries strongly depends on the thickness of the solid electrolyte interphase(SEI)formed on graphite anodes.Nevertheless,electrolyte decomposition at the anode surface,es...The electrochemical stability of lithium-ion batteries strongly depends on the thickness of the solid electrolyte interphase(SEI)formed on graphite anodes.Nevertheless,electrolyte decomposition at the anode surface,espe-cially at 65℃,leads to uncontrolled SEI growth.We have designed a hybrid negative electrode by incorporating hard carbon(HC)into graphite to increase the surface work function,which effectively hinders electron escape,thereby reducing electrolyte reduction and inhibiting thick SEI formation at 65℃.The disordered structure of HC faciitates lithiumion diffusion and prevents lithium plating on the electrode surface.As a result,a hybrid negative electrode containing 50%HC has an especially high capacity(98 mAh/g)at 8 C and long cycle life at 0.5 C at room temperature.Further-more,in a full battery it has an excellent capacity(128.54 mAh/g)and stable floating charge for 144 h at 65℃.The electrode achieves a balance between high energy density and high-power density for lithium-ion batteries,thus maintaining stability even during a floating charge at a temperature of 65℃.This is attributed to the formation of a thinner and more robust SEI.This study provides a mechanistic understanding of how the electrode work function governs electrolyte decomposition and SEI evolution,offering a practical strategy for slowing the degradation of lithium-ion batteries at 65℃.展开更多
文摘以“竹藤种质资源数据库”中126个竹种为基础数据,应用K均值聚类算法(K-means算法)、小批量K均值聚类算法(Mini Batch K means算法)、凝聚层次聚类算法,依据竹种酸不溶木质素、苯醇提取物、综纤维素、基本密度、纤维长度、纤维双壁厚、纤维壁腔比7个特征对竹种筛选分级,遴选优良造纸竹种,分析聚类算法对竹藤种质资源的聚类有效性。结果表明:K均值聚类算法具有最高的卡林斯其-哈瑞本斯(Calinski_Harabaz(CH))指标值(63.568),聚类效果最好,126个竹种分为3级。其中:Ⅰ级造纸竹种,包含糯竹、空竹等51个竹种,适合制作高级纸张;Ⅱ级造纸竹种,包括毛竹、思劳竹等62个竹种,适合在排污能力强的造纸厂做纸浆造纸原料。K均值聚类算法是竹种造纸适应性分析的高效可靠的方法,具有较好的应用前景。
基金supported by National Key Research and Development(R&D)Program of China(2022YFF0609802,2022YFF0609801)Fundamental Research Program of Shanxi Province(202403021222485,202403021222486)Talent Projects for Outstanding Doctoral Students to Work in Shanxi Province(2023SHB002)。
文摘The electrochemical stability of lithium-ion batteries strongly depends on the thickness of the solid electrolyte interphase(SEI)formed on graphite anodes.Nevertheless,electrolyte decomposition at the anode surface,espe-cially at 65℃,leads to uncontrolled SEI growth.We have designed a hybrid negative electrode by incorporating hard carbon(HC)into graphite to increase the surface work function,which effectively hinders electron escape,thereby reducing electrolyte reduction and inhibiting thick SEI formation at 65℃.The disordered structure of HC faciitates lithiumion diffusion and prevents lithium plating on the electrode surface.As a result,a hybrid negative electrode containing 50%HC has an especially high capacity(98 mAh/g)at 8 C and long cycle life at 0.5 C at room temperature.Further-more,in a full battery it has an excellent capacity(128.54 mAh/g)and stable floating charge for 144 h at 65℃.The electrode achieves a balance between high energy density and high-power density for lithium-ion batteries,thus maintaining stability even during a floating charge at a temperature of 65℃.This is attributed to the formation of a thinner and more robust SEI.This study provides a mechanistic understanding of how the electrode work function governs electrolyte decomposition and SEI evolution,offering a practical strategy for slowing the degradation of lithium-ion batteries at 65℃.
