It is a great challenge to prepare non-noble metal electrocatalysts toward hydrogen evolution reaction(HER)with large current density.Synergistic electronic and morphological structures of the catalyst have been consi...It is a great challenge to prepare non-noble metal electrocatalysts toward hydrogen evolution reaction(HER)with large current density.Synergistic electronic and morphological structures of the catalyst have been considered as an effective method to improve the catalytic performance,due to the enhanced intrinsic activity and enlarged accessible active sites.Herein,we present novel ternary Co_(1-x)V_(x)P nanoneedle arrays with modulated electronic and morphological structures as an electrocatalyst for highly efficient HER in alkaline solution.The NF@Co1-xVxP catalyst shows a remarkable catalytic ability with low overpotentials of 46 and 226 mV at current densities of 10 and 400 mA cm^(-2),respectively,as well as a small Tafel slope and superior stability.Combining the experimental and computational study,the excellent catalytic performance was attributed to the improved physical and chemical properties(conductivity and surface activity),large active surface area,and fast reaction kinetics.Furthermore,the assembled Co–V based electrolyzer(NF@Co_(1-x)V_(x)–HNNs(+)||NF@Co_(1-x)V_(x)P(-))delivers small full-cell voltages of 1.58,1.75,and 1.92 V at 10,100,and 300 mA cm^(-2),respectively.Our findings provide a systematic understanding on the V–incorporation strategy to promote highly efficient ternary electrocatalysts via synergistic control of morphology and electronic structures.展开更多
Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± ...Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± 2.27) kilograms (215 (± 5) pounds) of weight with strength-per-weight ratio up to 10,336 (± 240). So, strength has been discovered to be an emergent characteristic arising solely from addition of intelligent order. It is proposed to impose such intelligent order upon, preferably, at least 6 laser beams by focusing each of them to form cones of light, arranging the cones to form a wall of a larger fractal cone, and converging all of them to a common focal point inside a vacuum chamber to give them sufficient strength near this focal point to attract, hold, and move neutral antimatter, preferably anti-lithium. This opens the new field of structural engineering of light and re-defines the concept of strength. Means of cancelling out radiation pressure by reflection of laser beams back to the common focal point are proposed to enable laser confinement of particles having low polarizability, such as anti-hydrogen. Counter-circulation of light by reflection at grazing incidence is proposed as a means of returning escaping antimatter back to the common focal point containment area. Means are proposed to inject a stream of matter into the contained antimatter to create a matter-antimatter reactor and propulsion engine. Since anti-lithium is not available, yet, means are proposed to test these structures by confining ordinary lithium, instead, and by hitting it with anti-protons and/or positrons. Means are proposed to modulate the matter-antimatter reaction with information to create modulated gravitational waves for communication. The proposed structures would enable efficient, stable, safe confinement of antimatter, which would allow better study of antimatter, and make possible renewable, clean, safe, matter-antimatter reactor generators and propulsion engines, antimatter-assisted fusion reactors, and modula展开更多
The search for alternatives to traditional sources of electric energy opens the way for a new market in the world, and for Brazil in particular. Still in its first steps, but with immense potential, the generation of ...The search for alternatives to traditional sources of electric energy opens the way for a new market in the world, and for Brazil in particular. Still in its first steps, but with immense potential, the generation of energy from solar irradiation and hydroelectric plants in hybrid systems is an important alternative. On the other hand, single source power systems, when designed to meet a particular demand without fail, lead to low market acceptance due to the availability of resources and low efficiency in performance that rewards high initial investment costs. One solution to balance and optimize energy supply is the use of more than one energy resource when sources can be complementary. Among several possible combinations reported in several studies, the hybrid photovoltaic hydroelectric system is considered to be an optimal and interesting combination. In this context, the present article makes a technical and economic pre-feasibility analysis of a hydroelectric photovoltaic hybrid system, operating photovoltaic panels on floating structures on the water surface to allow the use of the Laranjeiras dam. The study was conducted based on simulations with HOMER. The solution indicated as optimal was the installation of a hybrid energy system, implementing a hydroelectric power plant at the base of the dam, with 1497 kW of installed capacity, operating simultaneously with a set of photovoltaic modules, on the water surface of the dam, with 180 kW of installed capacity, and a power limit for the purchase and sale to the grid equal to 400 kW, to supply the demand of consumer loads up to 40 MWh per day. This combination would result in an initial cost of US$3984.885 per kW and an energy cost of US$0.026 per kWh.展开更多
Seasonal variability coupled with the intermittency of renewable energy sources makes reservoir hydroelectric plants an interesting option to consider in hybrid energy systems, especially in cases of dams that have no...Seasonal variability coupled with the intermittency of renewable energy sources makes reservoir hydroelectric plants an interesting option to consider in hybrid energy systems, especially in cases of dams that have not been completed or have been abandoned and which still have some potential for reuse. The Laranjeiras dam was completed in the 1960s and the original project for hydroelectric power generation was not completed, made impossible by economic changes during the construction years. A recent study proposed the implementation of a hydroelectric photovoltaic hybrid system with lower horsepower to allow the dam to be made useful again. This paper presents the results of the computational simulations with the software Homer, considering the operation of the hydroelectric component (of the proposed hybrid system) with reservoir, playing the role of energy storage device when the production exceeds the demand at a given moment, reducing the loss of energy due to unavailability of demand. The study suggested to implement a hydroelectric power plant with power house at the base of the dam that has a height of 20 m, operating at a minimum flow of 9171 L/s, with reservoir operating as a device for energy storage, operating with a photovoltaic system of 360 kW, and a power limit for the purchase of energy from the grid equal to 200 kW, providing consumer loads up to 40 MWh per day, with cost of energy equal to US$0.021 per kWh and a capital cost of US$3285.617.展开更多
基金the National Natural Science Foundation of China(21671096,21603094 and21905180)the Natural Science Foundation of Guangdong Province(2018B030322001 and 2018A030310225)+4 种基金Shenzhen Peacock Plan(KQTD2016022620054656)Shenzhen Key Laboratory Project(ZDSYS201603311013489)the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen(JCYJ20190809115413414)the Science and Technology Development Fund from Macao SAR(FDCT–0102/2019/A2,FDCT–0035/2019/AGJ and FDCT–0154/2019/A3)the Multi-Year Research Grants(MYRG2017–00027–FST and MYRG2018–00003–IAPME)from the University of Macao。
文摘It is a great challenge to prepare non-noble metal electrocatalysts toward hydrogen evolution reaction(HER)with large current density.Synergistic electronic and morphological structures of the catalyst have been considered as an effective method to improve the catalytic performance,due to the enhanced intrinsic activity and enlarged accessible active sites.Herein,we present novel ternary Co_(1-x)V_(x)P nanoneedle arrays with modulated electronic and morphological structures as an electrocatalyst for highly efficient HER in alkaline solution.The NF@Co1-xVxP catalyst shows a remarkable catalytic ability with low overpotentials of 46 and 226 mV at current densities of 10 and 400 mA cm^(-2),respectively,as well as a small Tafel slope and superior stability.Combining the experimental and computational study,the excellent catalytic performance was attributed to the improved physical and chemical properties(conductivity and surface activity),large active surface area,and fast reaction kinetics.Furthermore,the assembled Co–V based electrolyzer(NF@Co_(1-x)V_(x)–HNNs(+)||NF@Co_(1-x)V_(x)P(-))delivers small full-cell voltages of 1.58,1.75,and 1.92 V at 10,100,and 300 mA cm^(-2),respectively.Our findings provide a systematic understanding on the V–incorporation strategy to promote highly efficient ternary electrocatalysts via synergistic control of morphology and electronic structures.
文摘Flat, straight sheets of paper, standing vertically on edge cannot support any load placed upon their top edge, but once formed into fractal tube conic sections, they have been measured to support up to 97.52 (± 2.27) kilograms (215 (± 5) pounds) of weight with strength-per-weight ratio up to 10,336 (± 240). So, strength has been discovered to be an emergent characteristic arising solely from addition of intelligent order. It is proposed to impose such intelligent order upon, preferably, at least 6 laser beams by focusing each of them to form cones of light, arranging the cones to form a wall of a larger fractal cone, and converging all of them to a common focal point inside a vacuum chamber to give them sufficient strength near this focal point to attract, hold, and move neutral antimatter, preferably anti-lithium. This opens the new field of structural engineering of light and re-defines the concept of strength. Means of cancelling out radiation pressure by reflection of laser beams back to the common focal point are proposed to enable laser confinement of particles having low polarizability, such as anti-hydrogen. Counter-circulation of light by reflection at grazing incidence is proposed as a means of returning escaping antimatter back to the common focal point containment area. Means are proposed to inject a stream of matter into the contained antimatter to create a matter-antimatter reactor and propulsion engine. Since anti-lithium is not available, yet, means are proposed to test these structures by confining ordinary lithium, instead, and by hitting it with anti-protons and/or positrons. Means are proposed to modulate the matter-antimatter reaction with information to create modulated gravitational waves for communication. The proposed structures would enable efficient, stable, safe confinement of antimatter, which would allow better study of antimatter, and make possible renewable, clean, safe, matter-antimatter reactor generators and propulsion engines, antimatter-assisted fusion reactors, and modula
文摘The search for alternatives to traditional sources of electric energy opens the way for a new market in the world, and for Brazil in particular. Still in its first steps, but with immense potential, the generation of energy from solar irradiation and hydroelectric plants in hybrid systems is an important alternative. On the other hand, single source power systems, when designed to meet a particular demand without fail, lead to low market acceptance due to the availability of resources and low efficiency in performance that rewards high initial investment costs. One solution to balance and optimize energy supply is the use of more than one energy resource when sources can be complementary. Among several possible combinations reported in several studies, the hybrid photovoltaic hydroelectric system is considered to be an optimal and interesting combination. In this context, the present article makes a technical and economic pre-feasibility analysis of a hydroelectric photovoltaic hybrid system, operating photovoltaic panels on floating structures on the water surface to allow the use of the Laranjeiras dam. The study was conducted based on simulations with HOMER. The solution indicated as optimal was the installation of a hybrid energy system, implementing a hydroelectric power plant at the base of the dam, with 1497 kW of installed capacity, operating simultaneously with a set of photovoltaic modules, on the water surface of the dam, with 180 kW of installed capacity, and a power limit for the purchase and sale to the grid equal to 400 kW, to supply the demand of consumer loads up to 40 MWh per day. This combination would result in an initial cost of US$3984.885 per kW and an energy cost of US$0.026 per kWh.
文摘Seasonal variability coupled with the intermittency of renewable energy sources makes reservoir hydroelectric plants an interesting option to consider in hybrid energy systems, especially in cases of dams that have not been completed or have been abandoned and which still have some potential for reuse. The Laranjeiras dam was completed in the 1960s and the original project for hydroelectric power generation was not completed, made impossible by economic changes during the construction years. A recent study proposed the implementation of a hydroelectric photovoltaic hybrid system with lower horsepower to allow the dam to be made useful again. This paper presents the results of the computational simulations with the software Homer, considering the operation of the hydroelectric component (of the proposed hybrid system) with reservoir, playing the role of energy storage device when the production exceeds the demand at a given moment, reducing the loss of energy due to unavailability of demand. The study suggested to implement a hydroelectric power plant with power house at the base of the dam that has a height of 20 m, operating at a minimum flow of 9171 L/s, with reservoir operating as a device for energy storage, operating with a photovoltaic system of 360 kW, and a power limit for the purchase of energy from the grid equal to 200 kW, providing consumer loads up to 40 MWh per day, with cost of energy equal to US$0.021 per kWh and a capital cost of US$3285.617.
