This paper focused on the influence of the shape and size of threshing frames as well as the grades of tobacco leaves on the structure of threshed leaves.The testing tobacco leaves all came from the hilly ecological r...This paper focused on the influence of the shape and size of threshing frames as well as the grades of tobacco leaves on the structure of threshed leaves.The testing tobacco leaves all came from the hilly ecological region of Nanling and belonged to burnt sweet,alcoholic sweet and scent category.The comprehensive evaluating value S was taken as the test index.Results showed that,without considering the influence of tobacco grade on leaf structure,the shapes of first-stage thresher five-link frames were all hexagons,and the combination with the sizes of 3.5,3.0,3.5,3.0,3.0 inches had the highest evaluating value S of 2.49.For tobacco grade C2FH,the shapes of first-stage thresher five-link frames were also hexagons,and the evaluating value S reached the highest value of 3.40 with sizes of 3.5,3.0,3.5,3.0,3.0 inches.Comprehensive analysis showed that:3.0 inch frame performed better in controlling the percentage of large-sized strips than 3.5 inch frame did;rhombic frames were better than hexagon frames in reducing the breakage rate of tobacco leaves;different shapes or sizes of nonadjacent two-link frames can help to improve the threshing quality.展开更多
Hong Kong has undergone substantial economic transformations and developed into a sophisticated busi- ness and financial center in the Asia-Pacific region, since the return of sovereignty to China as a Special Adminis...Hong Kong has undergone substantial economic transformations and developed into a sophisticated busi- ness and financial center in the Asia-Pacific region, since the return of sovereignty to China as a Special Administrative Region under the One Country Two Systems (OCTS) in 1997. This paper discusses and analyzes the industrial struc- tural changes of Hong Kong in recent decades as well as its future challenges and opportunities, The data and finding reveal that even though Hong Kong will face fierce competition from the Mainland's cities as the rise of China, the important role as a bridge between China and the rest of the world wilt brace Hong Kong itself under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region.展开更多
Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricit...Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricity from renewable sources.Efficient electrocatalysts allowing CO2 to be reduced selectively and actively are crucial since the ECR is a complex and sluggish process producing a variety of products.Metal-organic frameworks(MOFs)and covalentorganic frameworks(COFs)have emerged as versatile materials applicable in many fields due to their unique properties including high surface areas and tunable pore channels.Besides,the emerging reticular chemistry makes tuning their features on the atomic/molecular levels possible,thereby lending credence to the prospect of their utilizations.Herein,an overview of recent progress in employing framework material-based catalysts,including MOFs,COFs and their derivatives,for ECR is provided.The pertinent challenges,future trends,and opportunities associated with those systems are also discussed.展开更多
The neutrino-dominated disk is regarded as a plausible model for the central engine of Gamma-Ray Bursts. By taking into account magnetic fields and detailed microphysics, we calculate the structure of neutrino-dominat...The neutrino-dominated disk is regarded as a plausible model for the central engine of Gamma-Ray Bursts. By taking into account magnetic fields and detailed microphysics, we calculate the structure of neutrino-dominated disks in the frame of the well-known Paczy nski-Witta potential. The results show that the temperature of the disk is lower than that without magnetic fields, whereas the density is nearly the same as that without magnetic fields. There also exists a significant difference in the electron degeneracy between the above two cases. In addition, we present the variation of the electron fraction with the radius.展开更多
The hydrogen evolution reaction(HER)as a fundamental process in electrocatalysis plays a significant role in clean energy technologies.For an energy-efficient HER,it demands an effective,durable,and low-cost catalyst ...The hydrogen evolution reaction(HER)as a fundamental process in electrocatalysis plays a significant role in clean energy technologies.For an energy-efficient HER,it demands an effective,durable,and low-cost catalyst to trigger proton reduction with minimal overpotential and fast kinetics.Here,we successfully fabricate a highly efficient HER catalyst of N-C/Co/Mo_(2)C holey nanorods with Co/b-Mo_(2)C nanoparticles uniformly embedded in nitrogen-doped carbon(N-C/Co/Mo_(2)C)by pyrolyzing the molybdate-coordinated zeolitic imidazolate framework(ZIF-67/MoO_(4)^(2-))holey nanorods,which result from the reaction between CoMoO_(4)and Me IM in a methanol/water/triethylamine mixed solution.The uniform distribution of MoO_(4)^(2-)in the ZIF-67/MoO_(4)^(2-)enables Co/β-Mo_(2)C nanoparticles to be welldistributed within nitrogen-doped carbon holey nanorods.This synthetic strategy endows the N-C/Co/Mo_(2)C catalyst with uniformly decorated bimetal,thus attaining excellent HER electrocatalytic activities with a small overpotential of 142.0 m V at 10 m A cm^(-2)and superior stability in 1.0 mol L^(-1)KOH aqueous solution.展开更多
文摘This paper focused on the influence of the shape and size of threshing frames as well as the grades of tobacco leaves on the structure of threshed leaves.The testing tobacco leaves all came from the hilly ecological region of Nanling and belonged to burnt sweet,alcoholic sweet and scent category.The comprehensive evaluating value S was taken as the test index.Results showed that,without considering the influence of tobacco grade on leaf structure,the shapes of first-stage thresher five-link frames were all hexagons,and the combination with the sizes of 3.5,3.0,3.5,3.0,3.0 inches had the highest evaluating value S of 2.49.For tobacco grade C2FH,the shapes of first-stage thresher five-link frames were also hexagons,and the evaluating value S reached the highest value of 3.40 with sizes of 3.5,3.0,3.5,3.0,3.0 inches.Comprehensive analysis showed that:3.0 inch frame performed better in controlling the percentage of large-sized strips than 3.5 inch frame did;rhombic frames were better than hexagon frames in reducing the breakage rate of tobacco leaves;different shapes or sizes of nonadjacent two-link frames can help to improve the threshing quality.
基金Under the auspices of Hui Oi Chow Trust Fund(No.200902172004)Mrs.Li Ka Shing Fund,Strategic Research Theme on Contemporary China,Seed Funding Programme for Basic Research(No.200911159173)Seed Funding Programme for Applied Research(No.201102160031)
文摘Hong Kong has undergone substantial economic transformations and developed into a sophisticated busi- ness and financial center in the Asia-Pacific region, since the return of sovereignty to China as a Special Administrative Region under the One Country Two Systems (OCTS) in 1997. This paper discusses and analyzes the industrial struc- tural changes of Hong Kong in recent decades as well as its future challenges and opportunities, The data and finding reveal that even though Hong Kong will face fierce competition from the Mainland's cities as the rise of China, the important role as a bridge between China and the rest of the world wilt brace Hong Kong itself under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region.
基金financially supported by the National Natural Science Foundation of China(21671096 and 11775105)Shenzhen Peacock Plan(KQTD2016022620054656)。
文摘Electrochemical CO2 reduction(ECR)represents a promising strategy for utilizing CO2,an industrial waste,as an abundant and cheap carbon source for organic synthesis as well as storing intermittent renewable electricity from renewable sources.Efficient electrocatalysts allowing CO2 to be reduced selectively and actively are crucial since the ECR is a complex and sluggish process producing a variety of products.Metal-organic frameworks(MOFs)and covalentorganic frameworks(COFs)have emerged as versatile materials applicable in many fields due to their unique properties including high surface areas and tunable pore channels.Besides,the emerging reticular chemistry makes tuning their features on the atomic/molecular levels possible,thereby lending credence to the prospect of their utilizations.Herein,an overview of recent progress in employing framework material-based catalysts,including MOFs,COFs and their derivatives,for ECR is provided.The pertinent challenges,future trends,and opportunities associated with those systems are also discussed.
基金supported by the Innovation Program for Young Scientists of Fujian Province of China (Grant No. 2007F3105)
文摘The neutrino-dominated disk is regarded as a plausible model for the central engine of Gamma-Ray Bursts. By taking into account magnetic fields and detailed microphysics, we calculate the structure of neutrino-dominated disks in the frame of the well-known Paczy nski-Witta potential. The results show that the temperature of the disk is lower than that without magnetic fields, whereas the density is nearly the same as that without magnetic fields. There also exists a significant difference in the electron degeneracy between the above two cases. In addition, we present the variation of the electron fraction with the radius.
基金National Institute of Advanced Industrial Science and Technology(AIST)the Japan Society for the Promotion of Science(JSPS)for financial support。
文摘The hydrogen evolution reaction(HER)as a fundamental process in electrocatalysis plays a significant role in clean energy technologies.For an energy-efficient HER,it demands an effective,durable,and low-cost catalyst to trigger proton reduction with minimal overpotential and fast kinetics.Here,we successfully fabricate a highly efficient HER catalyst of N-C/Co/Mo_(2)C holey nanorods with Co/b-Mo_(2)C nanoparticles uniformly embedded in nitrogen-doped carbon(N-C/Co/Mo_(2)C)by pyrolyzing the molybdate-coordinated zeolitic imidazolate framework(ZIF-67/MoO_(4)^(2-))holey nanorods,which result from the reaction between CoMoO_(4)and Me IM in a methanol/water/triethylamine mixed solution.The uniform distribution of MoO_(4)^(2-)in the ZIF-67/MoO_(4)^(2-)enables Co/β-Mo_(2)C nanoparticles to be welldistributed within nitrogen-doped carbon holey nanorods.This synthetic strategy endows the N-C/Co/Mo_(2)C catalyst with uniformly decorated bimetal,thus attaining excellent HER electrocatalytic activities with a small overpotential of 142.0 m V at 10 m A cm^(-2)and superior stability in 1.0 mol L^(-1)KOH aqueous solution.