低空经济作为国家的重要战略部署,日益成为学术研究的焦点。基于Web of Science和中国知网数据库,运用科学计量与知识图谱分析方法,系统梳理2015-2025年低空经济领域的研究概况、知识基础、研究热点和演进脉络。研究发现,英文文献以技...低空经济作为国家的重要战略部署,日益成为学术研究的焦点。基于Web of Science和中国知网数据库,运用科学计量与知识图谱分析方法,系统梳理2015-2025年低空经济领域的研究概况、知识基础、研究热点和演进脉络。研究发现,英文文献以技术开发、场景应用、空域管理及商业模式创新为核心,注重技术驱动与商业生态融合;中文文献聚焦政策分析、空域划分与区域经济效益,注重制度创新与经济模式优化。当前,英文研究突出技术跨界融合,而中文研究在技术创新、商业模式和产业化路径方面具有潜力。未来研究需结合多学科视角,深化低空经济理论体系,关注其与数字经济的协同效应、社会经济影响评估及投融资模式创新,提升我国低空经济可持续发展能力和国际竞争力。展开更多
Ten soils collected from different parts of China were used in a series of experiments to study fixation of NH￣+_4 and K￣+ by soils. When K￣+ was added concurrently with or prior to NH￣+_4, the soils were found to...Ten soils collected from different parts of China were used in a series of experiments to study fixation of NH￣+_4 and K￣+ by soils. When K￣+ was added concurrently with or prior to NH￣+_4, the soils were found to fix more moles of NH￣+_4 than those of K￣+, irrespective of the mole ratios of NH￣+_4 to K￣+ that were added.展开更多
文摘低空经济作为国家的重要战略部署,日益成为学术研究的焦点。基于Web of Science和中国知网数据库,运用科学计量与知识图谱分析方法,系统梳理2015-2025年低空经济领域的研究概况、知识基础、研究热点和演进脉络。研究发现,英文文献以技术开发、场景应用、空域管理及商业模式创新为核心,注重技术驱动与商业生态融合;中文文献聚焦政策分析、空域划分与区域经济效益,注重制度创新与经济模式优化。当前,英文研究突出技术跨界融合,而中文研究在技术创新、商业模式和产业化路径方面具有潜力。未来研究需结合多学科视角,深化低空经济理论体系,关注其与数字经济的协同效应、社会经济影响评估及投融资模式创新,提升我国低空经济可持续发展能力和国际竞争力。
文摘Ten soils collected from different parts of China were used in a series of experiments to study fixation of NH￣+_4 and K￣+ by soils. When K￣+ was added concurrently with or prior to NH￣+_4, the soils were found to fix more moles of NH￣+_4 than those of K￣+, irrespective of the mole ratios of NH￣+_4 to K￣+ that were added.
