近年来,在经济增长过程中的资源环境约束日益凸显,绿色创新作为缓解这一问题的重要举措,已成为相关政府部门和众多学者关注的热点。以1998—2017年WOS(Web of Science)和CNKI收录的文献作为研究对象,运用CiteSpace文献计量方法分别从年...近年来,在经济增长过程中的资源环境约束日益凸显,绿色创新作为缓解这一问题的重要举措,已成为相关政府部门和众多学者关注的热点。以1998—2017年WOS(Web of Science)和CNKI收录的文献作为研究对象,运用CiteSpace文献计量方法分别从年代、作者、机构、国家、研究热点、演进趋势等方面进行分析。研究发现:2012年以后,绿色创新研究文献呈现出显著增长的趋势;目前国内外均未形成稳定的核心作者群;机构间的合作多数发生在同一国家或地区,跨国、跨区域的合作研究较少;热点研究领域主要集中在"工业生态学、生态创新、竞争优势"等六个方面。结合时区图谱,指出未来绿色创新领域的研究前沿。展开更多
Random fluctuations of turbulence bring random fluctuations of the refractive index, making the atmosphere a random fluctuation medium that destroys the coherence of light-waves. Research in atmospheric turbulence is ...Random fluctuations of turbulence bring random fluctuations of the refractive index, making the atmosphere a random fluctuation medium that destroys the coherence of light-waves. Research in atmospheric turbulence is actually the investigation of the atmospheric refractive index. The atmospheric structure constant of refractive index, C n 2 , is an important parameter denoting atmospheric turbulence. In this paper, C n 2 is measured during the day and at night and in all four seasons using a high sensitivity micro-thermal meter QHTP-2. The vertical profile of C n 2 in Hefei (0-30 km) is investigated by the analysis of experimental data. The average profile of C n 2 in Hefei exhibits conspicuous day and night differences with increased altitude. The distribution of log(C n 2 ) is nearly normal and has conspicuous seasonal differences.展开更多
In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analys...In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analysis of the flow stress and the friction-shearing stress of an H13 punch in steel squeeze casting process, the following results were obtained： if the flow stress of an H13 punch was smaller than its friction-shearing stress, these abnormal failures could not be avoided; and if there were some protection measures that enable the flow stress to have a greater value than its friction-shearing one, the abnormal failures would not occur. In the production of 45^# steel valves and catenary system components, the flow stress of a lateral H13 punch without any protection measure was about 29 MPa and its friction-shearing stress was about 51 MPa, then, the abnormal failures occurred; however, when the protection measures of the punch enabled its working temperature to have a value below 682 ℃ its flow stress was greater than its friction-shearing stress, and the abnormal failures were avoided.展开更多
文摘近年来,在经济增长过程中的资源环境约束日益凸显,绿色创新作为缓解这一问题的重要举措,已成为相关政府部门和众多学者关注的热点。以1998—2017年WOS(Web of Science)和CNKI收录的文献作为研究对象,运用CiteSpace文献计量方法分别从年代、作者、机构、国家、研究热点、演进趋势等方面进行分析。研究发现:2012年以后,绿色创新研究文献呈现出显著增长的趋势;目前国内外均未形成稳定的核心作者群;机构间的合作多数发生在同一国家或地区,跨国、跨区域的合作研究较少;热点研究领域主要集中在"工业生态学、生态创新、竞争优势"等六个方面。结合时区图谱,指出未来绿色创新领域的研究前沿。
基金supported by the National High Technology Research and Development Program of China (GrantNo. 2011AA8061007)
文摘Random fluctuations of turbulence bring random fluctuations of the refractive index, making the atmosphere a random fluctuation medium that destroys the coherence of light-waves. Research in atmospheric turbulence is actually the investigation of the atmospheric refractive index. The atmospheric structure constant of refractive index, C n 2 , is an important parameter denoting atmospheric turbulence. In this paper, C n 2 is measured during the day and at night and in all four seasons using a high sensitivity micro-thermal meter QHTP-2. The vertical profile of C n 2 in Hefei (0-30 km) is investigated by the analysis of experimental data. The average profile of C n 2 in Hefei exhibits conspicuous day and night differences with increased altitude. The distribution of log(C n 2 ) is nearly normal and has conspicuous seasonal differences.
文摘In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analysis of the flow stress and the friction-shearing stress of an H13 punch in steel squeeze casting process, the following results were obtained： if the flow stress of an H13 punch was smaller than its friction-shearing stress, these abnormal failures could not be avoided; and if there were some protection measures that enable the flow stress to have a greater value than its friction-shearing one, the abnormal failures would not occur. In the production of 45^# steel valves and catenary system components, the flow stress of a lateral H13 punch without any protection measure was about 29 MPa and its friction-shearing stress was about 51 MPa, then, the abnormal failures occurred; however, when the protection measures of the punch enabled its working temperature to have a value below 682 ℃ its flow stress was greater than its friction-shearing stress, and the abnormal failures were avoided.
