While alloying transition metal chalcogenides(TMCs)with other chalcogen elements can effectively improve their conductivity and electrochemical properties,the optimal alloying content is still uncertain.In this study,...While alloying transition metal chalcogenides(TMCs)with other chalcogen elements can effectively improve their conductivity and electrochemical properties,the optimal alloying content is still uncertain.In this study,we study the influence of dopant concentration on the chemical bonds in TMC and reveal the associated stepwise conversion reaction mechanism for potassium ion storage.According to density function theory calculations,appropriate S-doping in Co0.85Se(Co_(0.85)Se_(1-x)S_(x))can reduce the average length of Co-Co bonds because of the electronegativity variation,which is thermodynamically favourable to the phase transition reactions.The optimal Se/S ratio(x=0.12)for the conductivity has been obtained from experimental results.When assembled as an anode in potassium-ion batteries(PIBs),the sample with optimized Se/S ratio exhibits extraordinary electrochemical performance.The rate performance(229.2 mA h g^(-1)at 10 A g^(-1))is superior to the state-of-the-art results.When assembled with Prussian blue(PB)as a cathode,the pouch cell exhibits excellent performance,demonstrating its great potential for applications.Moreover,the stepwise K+storage mechanism caused by the coexistence of S and Se is revealed by in-situ X-ray diffraction and ex-situ transmission electron microscopy techniques.Hence,this work not only provides an effective strategy to enhance the electrochemical performance of transition metal chalcogenides but also reveals the underlying mechanism for the construction of advanced electrode materials.展开更多
A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,...A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,roasting temperature,roasting time,particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery ratio.The optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows:calcium oxide content of 25 wt.%,mixed gas flow rates of CO2 and CO of 180 and 20 mL/min,oxidizing roasting at 1323 K for 2 h,grinding the modified slag to 38.5-25.0μm and magnetic separation at 170 mT.The mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized,the generated magnetite grew into large particles,and the silicate in copper slag was combined with calcium oxide to form calcium silicate.Finally,the iron-bearing concentrate with an iron grade of 54.79%and iron recovery ratio of 80.14%was effectively obtained.展开更多
In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Ea...In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Earth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium and yttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationships for the induced effects between yttrium and neodymium as well as between gadolinium and neodymium have been determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured by alizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration may occur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometric determination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi- tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention must be paid to this area in the photometric determination of certain metals.展开更多
[目的/意义]基于科技基金共同资助的视角,探究区域联合创新现状,为构建高效且合理的区域创新协同机制提供有益参考。[方法/过程]以Web of Science数据库中国内地31个省级行政区为研究对象,通过复杂网络分析、逐步回归法等对区域联合创...[目的/意义]基于科技基金共同资助的视角,探究区域联合创新现状,为构建高效且合理的区域创新协同机制提供有益参考。[方法/过程]以Web of Science数据库中国内地31个省级行政区为研究对象,通过复杂网络分析、逐步回归法等对区域联合创新的布局态势及影响效果展开研究。[结果/结论]结果表明,从总体上看,东部地区参与共同资助的论文数量最多且学术影响力最高;各地区的区域联合创新水平逐年提高,对共同资助的依赖度不断降低;地缘邻近性和资源互补性是区域间以共同资助形式实现联合创新的主要驱动力;基准回归结果发现,论文数量和学术影响力对地区科技创新水平具有显著促进作用,论文数量的影响性稳定且持久,学术影响力和成果新颖性的影响效力更大,但持久性较弱,后者的促进作用有一定滞后性;异质性检验发现,论文数量和学术影响力对东部和西部地区科技创新水平的促进作用最大;递进影响分析表明,共同资助形式下的区域联合创新会成为赋能新质生产力的潜在动力。展开更多
基金financially supported by the Natural Science Foundation of Jiangsu Province of China(BK20211172)the Jiangsu Provincial Department of Science and Technology Innovation Support Program(BK20222004,BZ2022036)+1 种基金the National Natural Science Foundation of China(52002366,22075263)the Fundamental Research Funds for the Central Universities(WK2060000039)。
文摘While alloying transition metal chalcogenides(TMCs)with other chalcogen elements can effectively improve their conductivity and electrochemical properties,the optimal alloying content is still uncertain.In this study,we study the influence of dopant concentration on the chemical bonds in TMC and reveal the associated stepwise conversion reaction mechanism for potassium ion storage.According to density function theory calculations,appropriate S-doping in Co0.85Se(Co_(0.85)Se_(1-x)S_(x))can reduce the average length of Co-Co bonds because of the electronegativity variation,which is thermodynamically favourable to the phase transition reactions.The optimal Se/S ratio(x=0.12)for the conductivity has been obtained from experimental results.When assembled as an anode in potassium-ion batteries(PIBs),the sample with optimized Se/S ratio exhibits extraordinary electrochemical performance.The rate performance(229.2 mA h g^(-1)at 10 A g^(-1))is superior to the state-of-the-art results.When assembled with Prussian blue(PB)as a cathode,the pouch cell exhibits excellent performance,demonstrating its great potential for applications.Moreover,the stepwise K+storage mechanism caused by the coexistence of S and Se is revealed by in-situ X-ray diffraction and ex-situ transmission electron microscopy techniques.Hence,this work not only provides an effective strategy to enhance the electrochemical performance of transition metal chalcogenides but also reveals the underlying mechanism for the construction of advanced electrode materials.
基金The authors wish to express thanks to National Natural Science Foundation of China(Grant No.51774154)the Jiangxi Natural Science Foundation(Grant No.20151BAB206029)for the financial support for this research。
文摘A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,roasting temperature,roasting time,particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery ratio.The optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows:calcium oxide content of 25 wt.%,mixed gas flow rates of CO2 and CO of 180 and 20 mL/min,oxidizing roasting at 1323 K for 2 h,grinding the modified slag to 38.5-25.0μm and magnetic separation at 170 mT.The mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized,the generated magnetite grew into large particles,and the silicate in copper slag was combined with calcium oxide to form calcium silicate.Finally,the iron-bearing concentrate with an iron grade of 54.79%and iron recovery ratio of 80.14%was effectively obtained.
文摘In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef- fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-Rare Earth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium and yttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationships for the induced effects between yttrium and neodymium as well as between gadolinium and neodymium have been determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured by alizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration may occur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometric determination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi- tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention must be paid to this area in the photometric determination of certain metals.
文摘[目的/意义]基于科技基金共同资助的视角,探究区域联合创新现状,为构建高效且合理的区域创新协同机制提供有益参考。[方法/过程]以Web of Science数据库中国内地31个省级行政区为研究对象,通过复杂网络分析、逐步回归法等对区域联合创新的布局态势及影响效果展开研究。[结果/结论]结果表明,从总体上看,东部地区参与共同资助的论文数量最多且学术影响力最高;各地区的区域联合创新水平逐年提高,对共同资助的依赖度不断降低;地缘邻近性和资源互补性是区域间以共同资助形式实现联合创新的主要驱动力;基准回归结果发现,论文数量和学术影响力对地区科技创新水平具有显著促进作用,论文数量的影响性稳定且持久,学术影响力和成果新颖性的影响效力更大,但持久性较弱,后者的促进作用有一定滞后性;异质性检验发现,论文数量和学术影响力对东部和西部地区科技创新水平的促进作用最大;递进影响分析表明,共同资助形式下的区域联合创新会成为赋能新质生产力的潜在动力。
