Objective Ginkgoales and Czekanowskiales are important components of Mesozoic flora and were widely distributed in the Northern Hemisphere. They are usually preserved together in the stratum. Their fossils are abunda...Objective Ginkgoales and Czekanowskiales are important components of Mesozoic flora and were widely distributed in the Northern Hemisphere. They are usually preserved together in the stratum. Their fossils are abundant in the Middle Jurassic of Shaanxi Province, but there are no reports on their reproductive organs. Here, we report two male gymnospermous pollen cones from the Middle Jttrassic Yan'an Formation of the northeast Yulin City, Shaanxi Province, China. The characteristics of the fossils, including those of pollens, have been described in detail. The new specimens were compared with fossils closely similar in morphology, and the taxonomic affinity and systematies were established. The present results offer new fossil materials for the study of taxonomy, evolution, and phytogeography of Ginkgoales and Czekanowskiales.展开更多
we have synthesised a series of new optically nonlinear organic materials of cinnamylidene-acetophenone derivatives which have large nonl inear optical susceptibilities and short cut-off wavelengths.
Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the conti...Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the continental slope of the SW Dongsha Island in northern margin of the South China Sea (SCS). These mounds are characterized by hardened seabed, seafloor gas venting and folded structures, which implies the existence of active mud volcanoes. This work aims to confirm this speculation by seafloor sample dredging and to explore the potential of gas hydrates.展开更多
Double-layer organic electroluminescent devices have been constructed. A new fluorescent dye, 9,10-bis(phenylethynyl)anthracence, was chosen as the dopant which was molecularly dispersed in the polymer film, and green...Double-layer organic electroluminescent devices have been constructed. A new fluorescent dye, 9,10-bis(phenylethynyl)anthracence, was chosen as the dopant which was molecularly dispersed in the polymer film, and green light was observed from the device with luminance of 130cd/m(2) at 17V.展开更多
Wu Yue, a lung transplant recipi ent. now regards August 31, the day she underwent surgery, as her re-birth day. In the eyes' of many people, the 30-year- old woman is an embodiment of love, dili gence and intelligence.
Digital innovation is becoming increasingly important in today's economy. Many digital innovations are developed not within organizations, but in innovation-driven entrepreneurial ecosystems, where various entreprene...Digital innovation is becoming increasingly important in today's economy. Many digital innovations are developed not within organizations, but in innovation-driven entrepreneurial ecosystems, where various entrepreneurship related stakeholders collaborate and cooperate. Despite its significance, studies on digital entrepreneurship ecosystems (DEEs) are limited and the concept is largely undertheorized. This study intends to fill that gap by studying how a DEE organizes. This organizing issue is challenging, because stakeholders of a DEE are self-organizing and are not governed by any formal authority. To answer that question, we adopt forms of organizing as a theoretical lens, which provides structure to examine organizing issues. Through an in-depth case study of Zhongguancun, the Silicon Valley of China, we unveil eight processes around the themes of division of labor and integration of efforts. We further show that the forms of organizing feature a balance of centralized design and de-centralized emergence. This balanced view extends the forms of organizing literature, which takes an either/or perspective. Ecosystem architects and policy makers who intend to build entrepreneurship ecosystems to promote local economies can derive practical implications from our findings.展开更多
The nonlinear optical (NLO) and optical limiting (OL) properties of three new structures of organic NLO guest host Poly(N-vinylcarbozole)/disperse orange 3 (PVK/DO3), PVK/disperse orange 13 (PVK/DO13). and P...The nonlinear optical (NLO) and optical limiting (OL) properties of three new structures of organic NLO guest host Poly(N-vinylcarbozole)/disperse orange 3 (PVK/DO3), PVK/disperse orange 13 (PVK/DO13). and PVK/disperse orange 25 (PVK/DO25) as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X(3) compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.展开更多
基金financially supported by the Natural Science Foundation of China (grant No.41402023)
文摘Objective Ginkgoales and Czekanowskiales are important components of Mesozoic flora and were widely distributed in the Northern Hemisphere. They are usually preserved together in the stratum. Their fossils are abundant in the Middle Jurassic of Shaanxi Province, but there are no reports on their reproductive organs. Here, we report two male gymnospermous pollen cones from the Middle Jttrassic Yan'an Formation of the northeast Yulin City, Shaanxi Province, China. The characteristics of the fossils, including those of pollens, have been described in detail. The new specimens were compared with fossils closely similar in morphology, and the taxonomic affinity and systematies were established. The present results offer new fossil materials for the study of taxonomy, evolution, and phytogeography of Ginkgoales and Czekanowskiales.
文摘we have synthesised a series of new optically nonlinear organic materials of cinnamylidene-acetophenone derivatives which have large nonl inear optical susceptibilities and short cut-off wavelengths.
基金financially supported by the National Natural Science Foundation of China(grants No.41376062,91328205,41206039)Project of the Tectonic Evolution of China Sea and its adjacent areas(grant No.GZH201100205)+1 种基金Public Science and Technology Research Funds Projects of Ocean(grant No.201405032)sponsored by NSFC and Special Fund for strategic pilot technology,CAS
文摘Dongsha waters are poorly studied for gas hydrates. Previous multi-channel seismic reflection and Chirp sub- bottom profiles show that numerous submarine mounds stand up to 100 m high above the seafloor over the continental slope of the SW Dongsha Island in northern margin of the South China Sea (SCS). These mounds are characterized by hardened seabed, seafloor gas venting and folded structures, which implies the existence of active mud volcanoes. This work aims to confirm this speculation by seafloor sample dredging and to explore the potential of gas hydrates.
文摘Double-layer organic electroluminescent devices have been constructed. A new fluorescent dye, 9,10-bis(phenylethynyl)anthracence, was chosen as the dopant which was molecularly dispersed in the polymer film, and green light was observed from the device with luminance of 130cd/m(2) at 17V.
文摘Wu Yue, a lung transplant recipi ent. now regards August 31, the day she underwent surgery, as her re-birth day. In the eyes' of many people, the 30-year- old woman is an embodiment of love, dili gence and intelligence.
基金This research is supported by the National Natural Science Foundation of China (71402187), and Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China (15XNF023). For helpful comments, we thank two anonymous referees, English editor in FBR, Meng Zhao, Xiaoyu Ji, Shan Wang, Ruidong Zhang and the 2016 Frontiers of Business Research in China International Symposium.
文摘Digital innovation is becoming increasingly important in today's economy. Many digital innovations are developed not within organizations, but in innovation-driven entrepreneurial ecosystems, where various entrepreneurship related stakeholders collaborate and cooperate. Despite its significance, studies on digital entrepreneurship ecosystems (DEEs) are limited and the concept is largely undertheorized. This study intends to fill that gap by studying how a DEE organizes. This organizing issue is challenging, because stakeholders of a DEE are self-organizing and are not governed by any formal authority. To answer that question, we adopt forms of organizing as a theoretical lens, which provides structure to examine organizing issues. Through an in-depth case study of Zhongguancun, the Silicon Valley of China, we unveil eight processes around the themes of division of labor and integration of efforts. We further show that the forms of organizing feature a balance of centralized design and de-centralized emergence. This balanced view extends the forms of organizing literature, which takes an either/or perspective. Ecosystem architects and policy makers who intend to build entrepreneurship ecosystems to promote local economies can derive practical implications from our findings.
文摘The nonlinear optical (NLO) and optical limiting (OL) properties of three new structures of organic NLO guest host Poly(N-vinylcarbozole)/disperse orange 3 (PVK/DO3), PVK/disperse orange 13 (PVK/DO13). and PVK/disperse orange 25 (PVK/DO25) as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X(3) compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.
基金supported by the National Natural Science Foundation of China(32030016)the Natural Science Foundation of Shaanxi Province(2020JQ-149)+2 种基金the State Key Laboratory of Genetics Resources and Evolution(GREKF19-11)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University to Zeshan Linthe Shaanxi Program for Support of Topnotch Young Professionals to Lei Chen。