[Objective] The study aimed at evaluating the ability to save energy and reduce CO2 emission in China＇s cement industry. [Method] Based on long-term energy alternative planning system software （LEAP）, ＂LEAP of Ch...[Objective] The study aimed at evaluating the ability to save energy and reduce CO2 emission in China＇s cement industry. [Method] Based on long-term energy alternative planning system software （LEAP）, ＂LEAP of China＇s cement industry＂ model was established to simulate energy conservation and emission reduction in China＇s cement industry from 2010 to 2040 in different technologic situations. E ResultJ To save ener- gy and reduce CO2 emissions, new dry process kiln has priority over other technologies or measures, followed by equipment enlargement, mechani- cal shaft kiln, power generation system based on waste heat, as well as high-efficiency and energy-saving grinding technology, and new prepara- tion technology. If all the advanced technologies and measures are adopted, energy consumption and C02 emissions can be reduced by about 40.76% and 42.97% respectively. [ Condusion] LEAP of model is suitable for analyzing energy saving and emission reducing in China＇s cement industry and other industrial fields.展开更多
Based on the analysis of actual energy consumptions during stevia sugar production,practical measures were proposed to save energy（ gas,water and powder） consumption and reduce cost through waste heat recycle and ut...Based on the analysis of actual energy consumptions during stevia sugar production,practical measures were proposed to save energy（ gas,water and powder） consumption and reduce cost through waste heat recycle and utilization,process improvement,equipment operation efficiency,application of newly energysaving equipment,and some project applications were provided as case study for some techniques and methods adopted in the production.展开更多
The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking en...The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking energy feedback unit and battery energy storage unit is proposed,which provides green power for the station.In order to suppress the fluctuation of photovoltaic power generation and the intermittence of regenerative braking feedback energy,the energy management mode of microgrid is designed according to the illumination situation,braking energy feedback situation,battery state of charge and so on.In addition,a coordination control method based on virtual synchronous generator(VSG)is proposed to realize smooth switching among modes.Finally,the proposed energy management and coordination control method for elevated station microgrid is verified by Matlab/Simulink.The results show that the elevated station microgrid can operate safely and reliably under various energy management modes and realize smooth switching among modes.展开更多
Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues ob...Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.展开更多
Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with fr...Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with friendly ecological and environmental conditions, local energy resources should be considered. In this study, a mode of 'geothermal energy extraction-heat exchange-space heating-reinjection' was adopted to supply heat to resident houses in Hujiatai Village cooperating with a geothermal development entity based on the abundant geothermal resources, thereby constructing a clean, economic and autarkic new countryside energy system, which avoids utilization of fossil-energy, reduces emission of greenhouse gases and generation of solid coal cinder, protecting air and land environment, improving life quality of the people and building a typical model for Hebei Province and even for the whole country.展开更多
China should pilot renewable energy integration policies similar to those adopted in Germany and Texas in the Beijing-Tianjin-Hebei region to transmit excess energy and reduce wasted wind power.Renewable energy integr...China should pilot renewable energy integration policies similar to those adopted in Germany and Texas in the Beijing-Tianjin-Hebei region to transmit excess energy and reduce wasted wind power.Renewable energy integration will be fundamental to China?s transition to a low-carbon economy.Although China now leads the world in terms展开更多
A concept of energy saving & efficiency improving from cold source for cogeneration steam turbine was discussed herein. A new type "NCB" cogeneration steam turbine was proposed,which could considerably i...A concept of energy saving & efficiency improving from cold source for cogeneration steam turbine was discussed herein. A new type "NCB" cogeneration steam turbine was proposed,which could considerably increase heat supply capacity,thermal efficiency and electric power. Taking 300 MW cogeneration steam turbine as an example,the results show that heat supply capacity reaches the maximum,i.e. increases by 30 %,thermal efficiency is improved by 12 %,and electric power is enhanced by 15 MW during peak heat load.展开更多
In Kuwait air-conditioning systems consume approximately 70%of the grid energy during the long summer months.In this paper,various practical approaches are investigated to enhance the energy efficiency and decrease th...In Kuwait air-conditioning systems consume approximately 70%of the grid energy during the long summer months.In this paper,various practical approaches are investigated to enhance the energy efficiency and decrease the energy consumption of five existing air-conditioned(AC)buildings in Kuwait City.The process of energy management in air-conditioned buildings in Kuwait is overwhelming due to high energy consumption in the building sector.This study proposed an optimization technique for the proper energy management of installed AC systems to target energy-efficient buildings.In this study the aim is to explore the effect of different operating parameters,both theoretically and experimentally,and to contribute to the reduction of AC energy consumption.Consequently,the relationship between the thermal load in the air-conditioned buildings and the actual electrical energy consumption is determined,and remedial measures,along with different recom-mendations for energy saving,are presented.The actual thermal loads of each selected building were calculated and compared with the installed cooling capacity of the AC systems.From the results obtained it was concluded that,by implement-ing the suggested remedial measures,the predicted load in the selected buildings could be decreased significantly from the existing installed capacity of the cooling systems.Most of the remedial measures suggested for energy management lead to a reduction in power consumption and increased energy efficiency at different levels based on the specifications of the buildings considered and the AC systems installed,resulting in improved in economy,a reduced carbon footprint,and a cleaner environment.展开更多
Reducing power dissipation in electro-optic modulators is a key step for widespread application of silicon photonics to optical communication.In this work,we design Mach–Zehnder modulators in the silicon-on-insulator...Reducing power dissipation in electro-optic modulators is a key step for widespread application of silicon photonics to optical communication.In this work,we design Mach–Zehnder modulators in the silicon-on-insulator platform,which make use of slow light in a waveguide grating and of a reverse-biased p-n junction with interleaved contacts along the waveguide axis.After optimizing the junction parameters,we discuss the full simulation of the modulator in order to find a proper trade-off among various figures of merit,such as modulation efficiency,insertion loss,cutoff frequency,optical modulation amplitude,and dissipated energy per bit.Comparison with conventional structures(with lateral p-n junction and/or in rib waveguides without slow light)highlights the importance of combining slow light with the interleaved p-n junction,thanks to the increased overlap between the travelling optical wave and the depletion regions.As a surprising result,the modulator performance is improved over an optical bandwidth that is much wider than the slow-light bandwidth.展开更多
Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic ma...Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic materials,especially that of non-fullerene acceptors(NFAs),the OPV field has witnessed rapid progress with power conversion efficiency(PCE)exceeding 19%.However,it remains challenging to overcome the intrinsic trade-off between the photocurrent and photovoltage,restricting the further promotion of the OPV efficiency.In this regard,it is urgent to further tailor the structure of NFAs to broaden their absorption spectra while mitigating the energy loss of relevant devices concomitantly.Heteroatom substitution on the fused-ringπ-core of NFAs is an efficient way to achieve this goal.In addition to improve the nearinfrared light harvest by strengthening the intramolecular charge transfer,it can also enhance the molecular stacking via forming multiple noncovalent interactions,which is favorable for reducing the energetic disorder.Therefore,in this review we focus on the design rules of NFAs,including the polymerized NFAs,of which the core moiety is substituted by various kinds of heteroatoms.We also afford a comprehensive understanding on the structure–propertyperformance relationships of these NFAs.Finally,we anticipate the challenges restricting the efficiency promotion and industrial utilization of OPV,and provide potential solutions based on the further heteroatom optimization on NFA core-moiety.展开更多
Metal sulfides as a feasible candidate with high specific capacitance for supercapacitors suffer from sluggish ion/electron transport kinetics and rapid capacitance fading. Herein, we demonstrate a method to fabricate...Metal sulfides as a feasible candidate with high specific capacitance for supercapacitors suffer from sluggish ion/electron transport kinetics and rapid capacitance fading. Herein, we demonstrate a method to fabricate a composite of reduced graphene oxide（rGO） with hollow Co9S8 derived from metal organic framework（MOF）. Due to the combined highly conductive rGO substrates and hollow shell, the prepared r GO/Co9S8 composite exhibits a high specific capacitance of 575.9 F/g at 2 A/g and 92.0% capacitance retention after 9000 cycles. Its excellent electrochemical performance provides great promise for application, and this versatile method can be extended to prepare other similar nanocomposite.展开更多
基金Supported by Special Project for Developing National Major Scientific Instruments and Equipments (2011YQ060111)Scientific Research Project of Environmental Protection in Commonweal Industry(201009032)
文摘[Objective] The study aimed at evaluating the ability to save energy and reduce CO2 emission in China＇s cement industry. [Method] Based on long-term energy alternative planning system software （LEAP）, ＂LEAP of China＇s cement industry＂ model was established to simulate energy conservation and emission reduction in China＇s cement industry from 2010 to 2040 in different technologic situations. E ResultJ To save ener- gy and reduce CO2 emissions, new dry process kiln has priority over other technologies or measures, followed by equipment enlargement, mechani- cal shaft kiln, power generation system based on waste heat, as well as high-efficiency and energy-saving grinding technology, and new prepara- tion technology. If all the advanced technologies and measures are adopted, energy consumption and C02 emissions can be reduced by about 40.76% and 42.97% respectively. [ Condusion] LEAP of model is suitable for analyzing energy saving and emission reducing in China＇s cement industry and other industrial fields.
文摘Based on the analysis of actual energy consumptions during stevia sugar production,practical measures were proposed to save energy（ gas,water and powder） consumption and reduce cost through waste heat recycle and utilization,process improvement,equipment operation efficiency,application of newly energysaving equipment,and some project applications were provided as case study for some techniques and methods adopted in the production.
基金National Natural Science Foundation of China(No.51367010)Science and Technology Program of Gansu Province(No.17JR5RA083)Program for Excellent Team of Scientific Research in Lanzhou Jiaotong University(No.201701)
文摘The rapid development of urban rail transit brings convenience to the public,but its huge energy consumption problem cannot be ignored.A microgrid composed of photovoltaic power generation unit,regenerative braking energy feedback unit and battery energy storage unit is proposed,which provides green power for the station.In order to suppress the fluctuation of photovoltaic power generation and the intermittence of regenerative braking feedback energy,the energy management mode of microgrid is designed according to the illumination situation,braking energy feedback situation,battery state of charge and so on.In addition,a coordination control method based on virtual synchronous generator(VSG)is proposed to realize smooth switching among modes.Finally,the proposed energy management and coordination control method for elevated station microgrid is verified by Matlab/Simulink.The results show that the elevated station microgrid can operate safely and reliably under various energy management modes and realize smooth switching among modes.
文摘Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.
基金Supported by the Major Program of Water Resources Exploration in Beijing City(Exploration and Assessment Project of Karst Water Resources in Beijing City
文摘Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with friendly ecological and environmental conditions, local energy resources should be considered. In this study, a mode of 'geothermal energy extraction-heat exchange-space heating-reinjection' was adopted to supply heat to resident houses in Hujiatai Village cooperating with a geothermal development entity based on the abundant geothermal resources, thereby constructing a clean, economic and autarkic new countryside energy system, which avoids utilization of fossil-energy, reduces emission of greenhouse gases and generation of solid coal cinder, protecting air and land environment, improving life quality of the people and building a typical model for Hebei Province and even for the whole country.
文摘China should pilot renewable energy integration policies similar to those adopted in Germany and Texas in the Beijing-Tianjin-Hebei region to transmit excess energy and reduce wasted wind power.Renewable energy integration will be fundamental to China?s transition to a low-carbon economy.Although China now leads the world in terms
文摘A concept of energy saving & efficiency improving from cold source for cogeneration steam turbine was discussed herein. A new type "NCB" cogeneration steam turbine was proposed,which could considerably increase heat supply capacity,thermal efficiency and electric power. Taking 300 MW cogeneration steam turbine as an example,the results show that heat supply capacity reaches the maximum,i.e. increases by 30 %,thermal efficiency is improved by 12 %,and electric power is enhanced by 15 MW during peak heat load.
文摘In Kuwait air-conditioning systems consume approximately 70%of the grid energy during the long summer months.In this paper,various practical approaches are investigated to enhance the energy efficiency and decrease the energy consumption of five existing air-conditioned(AC)buildings in Kuwait City.The process of energy management in air-conditioned buildings in Kuwait is overwhelming due to high energy consumption in the building sector.This study proposed an optimization technique for the proper energy management of installed AC systems to target energy-efficient buildings.In this study the aim is to explore the effect of different operating parameters,both theoretically and experimentally,and to contribute to the reduction of AC energy consumption.Consequently,the relationship between the thermal load in the air-conditioned buildings and the actual electrical energy consumption is determined,and remedial measures,along with different recom-mendations for energy saving,are presented.The actual thermal loads of each selected building were calculated and compared with the installed cooling capacity of the AC systems.From the results obtained it was concluded that,by implement-ing the suggested remedial measures,the predicted load in the selected buildings could be decreased significantly from the existing installed capacity of the cooling systems.Most of the remedial measures suggested for energy management lead to a reduction in power consumption and increased energy efficiency at different levels based on the specifications of the buildings considered and the AC systems installed,resulting in improved in economy,a reduced carbon footprint,and a cleaner environment.
基金European Commission(H2020 Quant ERA ERA-NET Cofund QT project CUSPIDOR,H2020-ICT27-2015 project 688516 COSMICC)Ministero dell’Istruzione,dell’Universitàe della Ricerca+1 种基金Science Foundation Ireland(17/QERA/3472,12/RC/2276_P2)CINECA-ISCRA(Project Slow Mod-HP10C0BQ66)。
文摘Reducing power dissipation in electro-optic modulators is a key step for widespread application of silicon photonics to optical communication.In this work,we design Mach–Zehnder modulators in the silicon-on-insulator platform,which make use of slow light in a waveguide grating and of a reverse-biased p-n junction with interleaved contacts along the waveguide axis.After optimizing the junction parameters,we discuss the full simulation of the modulator in order to find a proper trade-off among various figures of merit,such as modulation efficiency,insertion loss,cutoff frequency,optical modulation amplitude,and dissipated energy per bit.Comparison with conventional structures(with lateral p-n junction and/or in rib waveguides without slow light)highlights the importance of combining slow light with the interleaved p-n junction,thanks to the increased overlap between the travelling optical wave and the depletion regions.As a surprising result,the modulator performance is improved over an optical bandwidth that is much wider than the slow-light bandwidth.
基金City University of Hong Kong,Grant/Award Number:9380086Innovation and Technology Commission of Hong Kong,Grant/Award Numbers:GHP/018/20SZ,MRP/040/21X+3 种基金Environment and Ecology Bureau of Hong Kong,Grant/Award Number:202020164Research Grants Council of Hong Kong,Grant/Award Numbers:11307621,C6023-19GFShenzhen Science and Technology Program,Grant/Award Number:SGDX20201103095412040Guangdong Major Project of Basic and Applied Basic Research,Grant/Award Number:2019B030302007。
文摘Organic photovoltaics(OPVs)represent one of the most promising photovoltaic technologies owing to their high capacity to convert solar energy to electricity.With the continuous structure upgradation of photovoltaic materials,especially that of non-fullerene acceptors(NFAs),the OPV field has witnessed rapid progress with power conversion efficiency(PCE)exceeding 19%.However,it remains challenging to overcome the intrinsic trade-off between the photocurrent and photovoltage,restricting the further promotion of the OPV efficiency.In this regard,it is urgent to further tailor the structure of NFAs to broaden their absorption spectra while mitigating the energy loss of relevant devices concomitantly.Heteroatom substitution on the fused-ringπ-core of NFAs is an efficient way to achieve this goal.In addition to improve the nearinfrared light harvest by strengthening the intramolecular charge transfer,it can also enhance the molecular stacking via forming multiple noncovalent interactions,which is favorable for reducing the energetic disorder.Therefore,in this review we focus on the design rules of NFAs,including the polymerized NFAs,of which the core moiety is substituted by various kinds of heteroatoms.We also afford a comprehensive understanding on the structure–propertyperformance relationships of these NFAs.Finally,we anticipate the challenges restricting the efficiency promotion and industrial utilization of OPV,and provide potential solutions based on the further heteroatom optimization on NFA core-moiety.
基金Financial support from National Key Project (No. 2017YFF0210703)Distinguished Young Scientists Program of the National Natural Science Foundation of China (Nos. 51425301, 21374021, 51673096 and U1601214)
文摘Metal sulfides as a feasible candidate with high specific capacitance for supercapacitors suffer from sluggish ion/electron transport kinetics and rapid capacitance fading. Herein, we demonstrate a method to fabricate a composite of reduced graphene oxide（rGO） with hollow Co9S8 derived from metal organic framework（MOF）. Due to the combined highly conductive rGO substrates and hollow shell, the prepared r GO/Co9S8 composite exhibits a high specific capacitance of 575.9 F/g at 2 A/g and 92.0% capacitance retention after 9000 cycles. Its excellent electrochemical performance provides great promise for application, and this versatile method can be extended to prepare other similar nanocomposite.
