为降低生产成本,江苏永钢集团有限公司采用Nb微合金化试制了HRB400E钢筋。以φ16 mm HRB400E钢筋为例,针对钢筋无屈服现象问题,对3种不同Nb含量钢筋的显微组织、析出物尺寸和分布、室温拉伸应力-应变曲线进行了分析。结果表明:由于含Nb...为降低生产成本,江苏永钢集团有限公司采用Nb微合金化试制了HRB400E钢筋。以φ16 mm HRB400E钢筋为例,针对钢筋无屈服现象问题,对3种不同Nb含量钢筋的显微组织、析出物尺寸和分布、室温拉伸应力-应变曲线进行了分析。结果表明:由于含Nb量较高的钢筋其固溶Nb量较多,同时由于精轧区域为升温轧制,尤其是小规格钢筋采用切分轧制工艺,终轧温度较高,降低了相变点温度,再加上小规格钢筋在冷床上的冷速较快,使其容易产生针状铁素体、贝氏体等低温异常组织,导致其无屈服现象。为此,对钢筋Nb含量及生产工艺进行了优化:将钢筋中Nb质量分数从0.035%减少到0.01%;铸坯加热温度控制为1100~1150℃;保证开轧温度为1050~1080℃、精轧入口温度为950~1000℃、终轧温度为1000~1050℃,以降低终轧后钢筋固溶Nb含量;上冷床温度控制为880~920℃,并在冷床上增加可调节的保温装置,对钢筋进行轧后缓冷,以延长珠光体转变时间,这是防止小规格钢筋冷速过快导致针状铁素体、贝氏体组织过多的关键技术。生产实践表明:上述工艺措施可有效避免钢筋出现针状铁素体、贝氏体组织,屈服平台不明显比例从0.51%降至0,解决了小规格含Nb钢筋屈服不明显的问题,降低了含Nb抗震钢筋的生产成本。展开更多
Carbon dots(CDs)have been extensively studied owing to their fascinating optical properties and wide potential applications.Here,we report an easy-to-perform and organic-solvent-free synthesis strategy for green-emiss...Carbon dots(CDs)have been extensively studied owing to their fascinating optical properties and wide potential applications.Here,we report an easy-to-perform and organic-solvent-free synthesis strategy for green-emissive CDs(G-CDs)possessing high photoluminescence(PL)quantum yield(QY).The G-CDs are synthesized by heating the homogeneous precursors of citric acid and cyanamide in an open vessel,circumventing the use of organic solvents,complex operations,high-pressure reactors,and expensive instruments in the synthesis process.The effect of various reaction variables on the formation and the optical properties of G-CDs are systematically investigated.The resultant G-CDs show bright PL emission at 521 nm with PL QY up to 73%.Then a white light-emitting diode(LED)with Commission Internationable de L'Eclairage(CIE)coordinates of(0.33,0.34)and color rendering index(CRI)of 92 is constructed based on G-CDs/thermoplastic polyurethane(TPU)composite.Moreover,a visual microfluidic detection platform is designed by using G-CDs as fluorescent probes for rapid quantitative detection of Fe^(3+),Cu^(2+),and Mn^(2+)metal ions,which can realize synchronized testing of multiple samples.This study might promote the development and preparation methods of high-performance CDs with various optical applications.展开更多
针对谷物产量分布研究中自主开发的系统或软件对于用户来说操作繁琐,及对向日葵测产研究较少的问题,文中采用HTML5+CSS+JavaScript、ArcGIS API for JavaScript、EChart、Access数据库等技术,设计一种基于WebGIS的向日葵产量远程监测平...针对谷物产量分布研究中自主开发的系统或软件对于用户来说操作繁琐,及对向日葵测产研究较少的问题,文中采用HTML5+CSS+JavaScript、ArcGIS API for JavaScript、EChart、Access数据库等技术,设计一种基于WebGIS的向日葵产量远程监测平台。首先,采用ASP.NET框架对平台前端可视界面进行总体样式设计,运用jQuery布局组件实现数据的可视化展示,并通过调用天地图API在线显示底图;其次,设计所需产量数据库表并进行后端编程,使前端界面与后端数据库进行数据交互。基于该设计平台,用户只需在通用浏览器内输入网址即可查询某个日期地块的向日葵产量分布图,实现远程在线查询的功能。最后,以内蒙古自治区红泥井村向日葵测产试验为例,对开发平台的功能进行应用。结果表明所开发平台简单、易操作,能够满足产量分布查询的实时性和便捷性要求,可为精准农业科学决策提供参考。展开更多
文摘为降低生产成本,江苏永钢集团有限公司采用Nb微合金化试制了HRB400E钢筋。以φ16 mm HRB400E钢筋为例,针对钢筋无屈服现象问题,对3种不同Nb含量钢筋的显微组织、析出物尺寸和分布、室温拉伸应力-应变曲线进行了分析。结果表明:由于含Nb量较高的钢筋其固溶Nb量较多,同时由于精轧区域为升温轧制,尤其是小规格钢筋采用切分轧制工艺,终轧温度较高,降低了相变点温度,再加上小规格钢筋在冷床上的冷速较快,使其容易产生针状铁素体、贝氏体等低温异常组织,导致其无屈服现象。为此,对钢筋Nb含量及生产工艺进行了优化:将钢筋中Nb质量分数从0.035%减少到0.01%;铸坯加热温度控制为1100~1150℃;保证开轧温度为1050~1080℃、精轧入口温度为950~1000℃、终轧温度为1000~1050℃,以降低终轧后钢筋固溶Nb含量;上冷床温度控制为880~920℃,并在冷床上增加可调节的保温装置,对钢筋进行轧后缓冷,以延长珠光体转变时间,这是防止小规格钢筋冷速过快导致针状铁素体、贝氏体组织过多的关键技术。生产实践表明:上述工艺措施可有效避免钢筋出现针状铁素体、贝氏体组织,屈服平台不明显比例从0.51%降至0,解决了小规格含Nb钢筋屈服不明显的问题,降低了含Nb抗震钢筋的生产成本。
基金supported by National Natural Science Foundation of China(Nos.21736006 and 21978132)National Key Research and Development Program of China(No.2022YFC2104600)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Carbon dots(CDs)have been extensively studied owing to their fascinating optical properties and wide potential applications.Here,we report an easy-to-perform and organic-solvent-free synthesis strategy for green-emissive CDs(G-CDs)possessing high photoluminescence(PL)quantum yield(QY).The G-CDs are synthesized by heating the homogeneous precursors of citric acid and cyanamide in an open vessel,circumventing the use of organic solvents,complex operations,high-pressure reactors,and expensive instruments in the synthesis process.The effect of various reaction variables on the formation and the optical properties of G-CDs are systematically investigated.The resultant G-CDs show bright PL emission at 521 nm with PL QY up to 73%.Then a white light-emitting diode(LED)with Commission Internationable de L'Eclairage(CIE)coordinates of(0.33,0.34)and color rendering index(CRI)of 92 is constructed based on G-CDs/thermoplastic polyurethane(TPU)composite.Moreover,a visual microfluidic detection platform is designed by using G-CDs as fluorescent probes for rapid quantitative detection of Fe^(3+),Cu^(2+),and Mn^(2+)metal ions,which can realize synchronized testing of multiple samples.This study might promote the development and preparation methods of high-performance CDs with various optical applications.
文摘针对谷物产量分布研究中自主开发的系统或软件对于用户来说操作繁琐,及对向日葵测产研究较少的问题,文中采用HTML5+CSS+JavaScript、ArcGIS API for JavaScript、EChart、Access数据库等技术,设计一种基于WebGIS的向日葵产量远程监测平台。首先,采用ASP.NET框架对平台前端可视界面进行总体样式设计,运用jQuery布局组件实现数据的可视化展示,并通过调用天地图API在线显示底图;其次,设计所需产量数据库表并进行后端编程,使前端界面与后端数据库进行数据交互。基于该设计平台,用户只需在通用浏览器内输入网址即可查询某个日期地块的向日葵产量分布图,实现远程在线查询的功能。最后,以内蒙古自治区红泥井村向日葵测产试验为例,对开发平台的功能进行应用。结果表明所开发平台简单、易操作,能够满足产量分布查询的实时性和便捷性要求,可为精准农业科学决策提供参考。
