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The geography of intercity technological proximity: evidence from China
Yingcheng Li,Weiting Xiong,Xiaowu Hu 서울시립대학교 도시과학연구원 2023 도시과학국제저널 Vol.27 No.3
In the context of a globalizing knowledge economy, cities have become more technologically proximate due to the increasing exchanges of people, information, and knowledge. However, technological proximity at the city level has gained relatively little attention within the vast literature on proximity. Drawing upon detailed address information on nearly 3.6 million invention patents that were applied in China between 2012 and 2016, this paper investigates the geography of intercity technological proximity among 286 Chinese cities. Technological proximity is measured by comparing cities’ technological profiles which are represented by the distribution of different classifications of patenting activity in which cities specialize. The empirical results show that the level of intercity technological proximity among Chinese cities has been generally on the rise. Moreover, there is strong spatial political bias in the geography of intercity technological proximity, with geographical proximity and institutional proximity having played a significantly positive role in facilitating intercity technological proximity.
Xin Zhao,Fangchao Cheng,Yingcheng Hu 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1
Cellulose nanofibrils (CNFs) were successfully isolated from agro-industrial waste (cornstalk, corn flesh, andcorncob) by subjecting the raw materials to organosolv and peroxide treatment, followed by ultrasonication. A detailedcomparative study was performed. Characterization results showed that the CNFs from cornstalk (CS) exhibited higher yieldand lignin content (20.81 %), compared with CNFs from corn flesh (CF) and corncob (CC). The CNFs from CF and CCexhibited similar morphology, particle size, crystallinity, and thermal stability but showed improved ultraviolet blockingability and optical transparency relative to those of CS. The CNFs from CF showed higher dispersion stability andmechanical properties than those from CS and CC. Peroxide treatment negatively influenced crystallinity and thermalstability, but exerted no apparent effect on optical transparency and mechanical strength. Thus, this study demonstrates thatagro-industrial wastes are sustainable resources for CNF production, which can potentially have a wide range of value-addedapplications. Ionic liquid-aided solvothermal treatment followed by ultrasonication is a facile and ideal method to produceCNFs with ultraviolet blocking ability.
Shuguang Li,Yanxia Feng,Jiankun Qin,Shuai Li,Gaoyuan Ye,Yingcheng Hu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10
In this study, a bi-directional corrugated lattice sandwich structure was fabricated from jute fibers and epoxy resin. Die casting was used to prepare the core struts and face sheets and two fiber composites were designed to produce structuralstruts. The configuration and the relative density of the core layer were altered. In addition, the three-point bending propertiesof each configuration were investigated to explore the various modes of failure, destruction processes, and mechanicalproperties. Results of the experiments show that failure mainly occurs via three modes: face sheet crushing, face sheetwrinkling, and core member crushing. Moreover, the failure mode is related to the strength of the core struts. Theoreticalcalculations and finite element analysis were carried out, and the simulation results were in good agreement withexperimental results, the relative errors of displacement and load are all within 20 %. In conclusion, the proposed sandwichbeam configuration composed of jute fibers could be highly useful for enhancing engineering structurer owing to the simplefabrication process, moreover, the materials are environmentally friendly and inexpensive.