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The local effects of an innovation: Evidence from the French fish market 期刊论文
ECOLOGICAL ECONOMICS, 2020, 171
作者:  Gobillon, Laurent;  Wolff, Francois-Charles
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/02
Fish  Innovation  Product quality  Product prices  Discontinuity  Difference in differences  
Gram-scale bottom-up flash graphene synthesis 期刊论文
NATURE, 2020, 577 (7792) : 647-651
作者:  Long, Haizhen;  Zhang, Liwei;  Lv, Mengjie;  Wen, Zengqi;  Zhang, Wenhao;  Chen, Xiulan;  Zhang, Peitao;  Li, Tongqing;  Chang, Luyuan;  Jin, Caiwei;  Wu, Guozhao;  Wang, Xi;  Yang, Fuquan;  Pei, Jianfeng;  Chen, Ping;  Margueron, Raphael;  Deng, Haiteng;  Zhu, Mingzhao;  Li, Guohong
收藏  |  浏览/下载:38/0  |  提交时间:2020/07/03

Most bulk-scale graphene is produced by a top-down approach, exfoliating graphite, which often requires large amounts of solvent with high-energy mixing, shearing, sonication or electrochemical treatment(1-3). Although chemical oxidation of graphite to graphene oxide promotes exfoliation, it requires harsh oxidants and leaves the graphene with a defective perforated structure after the subsequent reduction step(3,4). Bottom-up synthesis of high-quality graphene is often restricted to ultrasmall amounts if performed by chemical vapour deposition or advanced synthetic organic methods, or it provides a defect-ridden structure if carried out in bulk solution(4-6). Here we show that flash Joule heating of inexpensive carbon sources-such as coal, petroleum coke, biochar, carbon black, discarded food, rubber tyres and mixed plastic waste-can afford gram-scale quantities of graphene in less than one second. The product, named flash graphene (FG) after the process used to produce it, shows turbostratic arrangement (that is, little order) between the stacked graphene layers. FG synthesis uses no furnace and no solvents or reactive gases. Yields depend on the carbon content of the source  when using a high-carbon source, such as carbon black, anthracitic coal or calcined coke, yields can range from 80 to 90 per cent with carbon purity greater than 99 per cent. No purification steps are necessary. Raman spectroscopy analysis shows a low-intensity or absent D band for FG, indicating that FG has among the lowest defect concentrations reported so far for graphene, and confirms the turbostratic stacking of FG, which is clearly distinguished from turbostratic graphite. The disordered orientation of FG layers facilitates its rapid exfoliation upon mixing during composite formation. The electric energy cost for FG synthesis is only about 7.2 kilojoules per gram, which could render FG suitable for use in bulk composites of plastic, metals, plywood, concrete and other building materials.


Flash Joule heating of inexpensive carbon sources is used to produce gram-scale quantities of high-quality graphene in under a second, without the need for a furnace, solvents or reactive gases.


  
Does the design matter? Comparing satellite-based indices for insuring pastoralists against drought 期刊论文
ECOLOGICAL ECONOMICS, 2019, 162: 59-73
作者:  Jensen, Nathaniel;  Stoeffler, Quentin;  Fava, Francesco;  Vrieling, Anton;  Atzberger, Clement;  Meroni, Michele;  Mude, Andrew;  Carter, Michael
收藏  |  浏览/下载:26/0  |  提交时间:2019/11/27
Index insurance  Contract design  Product quality  Basis risk  
China's Green Lights Program: A review and assessment 期刊论文
ENERGY POLICY, 2017, 110
作者:  Guo, Fei;  Pachauri, Shonali
收藏  |  浏览/下载:18/0  |  提交时间:2019/04/09
Green Lights Program  Efficient lighting products  Policy assessment  Product quality control  China