The hydraulic system is the key component in the widely used wave energy converters(WEC).In this paper,we theoretically analyze and describe our investigation of the efficiency of the hydraulic system by simulation an...The hydraulic system is the key component in the widely used wave energy converters(WEC).In this paper,we theoretically analyze and describe our investigation of the efficiency of the hydraulic system by simulation and model testing of the combined heaving-buoy WEC.We derive a new governing equation that includes nonlinear hydraulic resistance in the power take-off(PTO).We conducted a physical model experiment based on a 100-kW prototype and applied a hydraulic system with an energy accumulator.The model test results reveal an important parameter related to efficiency with respect to nonlinear hydraulic resistance.We also studied the relationship between the efficiency and the initial conditions.Finally,based on our numerical simulation results,we discuss the effect on efficiency of the gas content of the hydraulic fluid and ways to reduce its impact.展开更多
While living in the century of crisis （of energy and water）, more focus should be given on renewable energy. Since Kosovo is more limited in hydro-energy resources than the neighboring countries, it is essential to ...While living in the century of crisis （of energy and water）, more focus should be given on renewable energy. Since Kosovo is more limited in hydro-energy resources than the neighboring countries, it is essential to study them and put to use more efficiently. Subject of this study is Istog spring as it is the most important spring of Mokra Gora together with Vrella and White Drino. The spring is analyzed as a complex resource on water economy providing： fish （trout）, potable water, water for irrigation and hydro-energy （currently not in function）. The focus of the study remains the hydro-energetic component, not just a revitalization process but as an upgrade of the existing facility to increase the capacity by 2-3 times. This study is based on information selection and processing regarding detailed technical and economic analysis providing a method for other springs that will be studied in the future. Two technical solutions to the problem are provided as the best economical and technical solution. Solution I has one level and a calculated flow of 7.5 m^3/s and consists generally of renovation works on existing facilities; Solution 2 plans the construction of another level 3 m lower than the existing one, increasing so both the hydro-power capacity and implementation cost for the project Both solutions provide little to no impact on the spring main attributes. The valley ecology will not be influenced because the water after HPP （Hydro Power Plant） will be flowing in its own bed. After this study, Istog spring will be more attractive to donors and will contribute in improvement of energetic structure in Kosovo that for the time being is poor in hydro component.展开更多
Under the dual pressures of economic growth and environmental protection,how to curb pollution and raise public welfare without harming the economy or with minimal economic output losses has become a major question fa...Under the dual pressures of economic growth and environmental protection,how to curb pollution and raise public welfare without harming the economy or with minimal economic output losses has become a major question facing China in its efforts to transform growth pattern and accomplish economic transition. On the basis of an overlapping generation(OLG) model, this paper introduces the health effects of environmental pollution to systematically discuss the optimal distribution ratio of energy tax revenues in subsidizing household income and emission abatement under given tax rates to reduce the risks of "environment-health-poverty" trap. Our research shows that an optimal distribution ratio for maximizing per capita output or an optimal distribution ratio for maximizing public welfare exists. Based on China's actual parameters, however, this study has found that China's energy tax revenue distribution policy hardly meets the two optimal targets at the same time. Specific distribution ratio is subject to government decision-making preference, and needs to be adjusted according to actual differences.展开更多
Organic-inorganic hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, the optical bandgap of CH3NH3PbI3 perovskite is stil...Organic-inorganic hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, the optical bandgap of CH3NH3PbI3 perovskite is still disputed. In order to comprehend the intrinsic characteristics of these materials, we study the near-band-edge optical responses of the solution-processed CH3NH3PbI3 perovskite crystals by photoconductivity and reflectance spectroscopy at room temperature. All these spectra of the CH3NH3PbI3 polycrystals show only one significant absorption edge at 1.58 eV. However, we observe an extra absorption edge at 1.47 eV in CH3NH3PbI3 single crystal. We establish a simple kinetic model of charge annihilation processes to explain why the low-energy structure of the photoconductivity and diffuse reflectance spectra of CH3NH3PbI3 polyerystals disappear, which provides another possibility for understanding the difference in absorption edge. It is noteworthy that this low-energy absorption edge of CH3NH3PbI3 single crystal has, to the best of our knowledge, seldom been reported on organic-inorganic hybrid perovskites. Therefore, the CH3NH3PbI3 single crystal exhibits a relatively wide absorption which makes it a promising candidate for photoelectric applications.展开更多
基金the support of the Marine Renewable Energy Project(No.GHME2016YY02)the National Natural Science Foundation of China(Nos.41376100 and 41706100)+1 种基金the Shandong Provincial Natural Science Key Basic Program(No.ZR2017ZA0202)the Fundamental Research Funds for the Central Universities(No.201564005)
文摘The hydraulic system is the key component in the widely used wave energy converters(WEC).In this paper,we theoretically analyze and describe our investigation of the efficiency of the hydraulic system by simulation and model testing of the combined heaving-buoy WEC.We derive a new governing equation that includes nonlinear hydraulic resistance in the power take-off(PTO).We conducted a physical model experiment based on a 100-kW prototype and applied a hydraulic system with an energy accumulator.The model test results reveal an important parameter related to efficiency with respect to nonlinear hydraulic resistance.We also studied the relationship between the efficiency and the initial conditions.Finally,based on our numerical simulation results,we discuss the effect on efficiency of the gas content of the hydraulic fluid and ways to reduce its impact.
文摘While living in the century of crisis （of energy and water）, more focus should be given on renewable energy. Since Kosovo is more limited in hydro-energy resources than the neighboring countries, it is essential to study them and put to use more efficiently. Subject of this study is Istog spring as it is the most important spring of Mokra Gora together with Vrella and White Drino. The spring is analyzed as a complex resource on water economy providing： fish （trout）, potable water, water for irrigation and hydro-energy （currently not in function）. The focus of the study remains the hydro-energetic component, not just a revitalization process but as an upgrade of the existing facility to increase the capacity by 2-3 times. This study is based on information selection and processing regarding detailed technical and economic analysis providing a method for other springs that will be studied in the future. Two technical solutions to the problem are provided as the best economical and technical solution. Solution I has one level and a calculated flow of 7.5 m^3/s and consists generally of renovation works on existing facilities; Solution 2 plans the construction of another level 3 m lower than the existing one, increasing so both the hydro-power capacity and implementation cost for the project Both solutions provide little to no impact on the spring main attributes. The valley ecology will not be influenced because the water after HPP （Hydro Power Plant） will be flowing in its own bed. After this study, Istog spring will be more attractive to donors and will contribute in improvement of energetic structure in Kosovo that for the time being is poor in hydro component.
基金a result of Preponderant Discipline(Industrial Economics)of Chinese Academy of Social SciencesNational Major Social Sciences Project(15ZDA054)+1 种基金the National Social Science Fund of China(NSSFC)(71273261,71573258)supported by the High-level Talent Attraction Program of Jinan University(88016557)
文摘Under the dual pressures of economic growth and environmental protection,how to curb pollution and raise public welfare without harming the economy or with minimal economic output losses has become a major question facing China in its efforts to transform growth pattern and accomplish economic transition. On the basis of an overlapping generation(OLG) model, this paper introduces the health effects of environmental pollution to systematically discuss the optimal distribution ratio of energy tax revenues in subsidizing household income and emission abatement under given tax rates to reduce the risks of "environment-health-poverty" trap. Our research shows that an optimal distribution ratio for maximizing per capita output or an optimal distribution ratio for maximizing public welfare exists. Based on China's actual parameters, however, this study has found that China's energy tax revenue distribution policy hardly meets the two optimal targets at the same time. Specific distribution ratio is subject to government decision-making preference, and needs to be adjusted according to actual differences.
基金supported by the National Natural Science Foundation of China(Grant Nos.11574302,61474114,61674141,61504134,21503209&11704032)the National Basic Research Program of China(Grant Nos.2015CB921503,2014CB643503&2013CB632805)+1 种基金National Key Research and Development Program(Grant Nos.2016YFB0402303&2016YFB0400101)Key Research Program of Frontier Science,Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH006)
文摘Organic-inorganic hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, the optical bandgap of CH3NH3PbI3 perovskite is still disputed. In order to comprehend the intrinsic characteristics of these materials, we study the near-band-edge optical responses of the solution-processed CH3NH3PbI3 perovskite crystals by photoconductivity and reflectance spectroscopy at room temperature. All these spectra of the CH3NH3PbI3 polycrystals show only one significant absorption edge at 1.58 eV. However, we observe an extra absorption edge at 1.47 eV in CH3NH3PbI3 single crystal. We establish a simple kinetic model of charge annihilation processes to explain why the low-energy structure of the photoconductivity and diffuse reflectance spectra of CH3NH3PbI3 polyerystals disappear, which provides another possibility for understanding the difference in absorption edge. It is noteworthy that this low-energy absorption edge of CH3NH3PbI3 single crystal has, to the best of our knowledge, seldom been reported on organic-inorganic hybrid perovskites. Therefore, the CH3NH3PbI3 single crystal exhibits a relatively wide absorption which makes it a promising candidate for photoelectric applications.
