China’s Dongfang Electric Machinery successfully completed the manufacturing of the first batch of embedded components for six turbines it is supplying for the Koysha Hydroelectric Dam project in Ethiopia.Transported...China’s Dongfang Electric Machinery successfully completed the manufacturing of the first batch of embedded components for six turbines it is supplying for the Koysha Hydroelectric Dam project in Ethiopia.Transported by land and sea,these parts will arrive on site in three months.Once completed,the power plant will generate more than 6 billion kwh of electricity annually,reducing carbon dioxide emissions by 1 million tonnes per year.展开更多
The rapid evolution and expanding scale of AI(artificial intelligence)technologies exert unprecedented energy demands on global electrical grids.Powering computationally intensive tasks such as large-scale AI model tr...The rapid evolution and expanding scale of AI(artificial intelligence)technologies exert unprecedented energy demands on global electrical grids.Powering computationally intensive tasks such as large-scale AI model training and widespread real-time inference necessitates substantial electricity consumption,presenting a significant challenge to conventional power infrastructure.This paper examines the critical need for a fundamental shift towards smart energy grids in response to AI’s growing energy footprint.It delves into the symbiotic relationship wherein AI acts as a significant energy consumer while offering the intelligence required for dynamic load management,efficient integration of renewable energy sources,and optimized grid operations.We posit that advanced smart grids are indispensable for facilitating AI’s sustainable growth,underscoring this synergy as a pivotal advancement toward a resilient energy future.展开更多
16 September 2013, Shenzhen--ZTE today unveiled the world＇s first flexible, reconfigurable terabit router that allows customers to build the highest-performance broadband networks. The terabit router supports the de...16 September 2013, Shenzhen--ZTE today unveiled the world＇s first flexible, reconfigurable terabit router that allows customers to build the highest-performance broadband networks. The terabit router supports the deployment of multiple line cards with processing capabilities of 10 Gbps to 1 Tbps. It also supports the deployment of modules that can scale throughput from 200 Gbps to 18 Tbps. For easy installation in a range of environments, the router interfaces are flexible and the component design is loose-coupled. This allows customers to customize networks to their needs and promotes adaptability, consistency, and continuity.展开更多
MORE than 1,000 Ghanaians are benefiting directly by way of jobs from a $600 million Sunon Asogli Thermal Power Plant （Ghana） Limited project - a power generating plant established in the Kpone-Tema metropolis, one ...MORE than 1,000 Ghanaians are benefiting directly by way of jobs from a $600 million Sunon Asogli Thermal Power Plant （Ghana） Limited project - a power generating plant established in the Kpone-Tema metropolis, one of the highly industrialized metropolitan areas in Ghana.展开更多
In order to meet the self-powered requirement by microelectronic products and micro-electrostatic vibration generator and avoid the environmental pollution caused by waste batteries,many countries have started their r...In order to meet the self-powered requirement by microelectronic products and micro-electrostatic vibration generator and avoid the environmental pollution caused by waste batteries,many countries have started their researches on piezoelectric power generation based on the researches on the recovery device of rotational energy of piezoelectric effect.The piezoelectric power generation has many advantages compared with other generation patterns.The piezoelectric power generation has become a new field of research.In this study,the piezoelectric vibrators were used to convert energy.According to the requirements by tire pressure alarm system,the energy conversion and storage were researched and analyzed by using the passive sensing device used in automotive inspection.The converted energy was then provided to the alarm,achieving intelligent control and utilization of piezoelectric vibrators.展开更多
The wind-assisted propulsion system is becoming one of the most popular and efficient ways to reduce both fuel consumption and carbon dioxide emission from the ships.In this study,several analyses have been carried ou...The wind-assisted propulsion system is becoming one of the most popular and efficient ways to reduce both fuel consumption and carbon dioxide emission from the ships.In this study,several analyses have been carried out on a model of bulk carrier fitted with five rigid sails with a 180°rotating mechanism for maximum usage of wind power and a telescopic reefing mechanism for folding it during berthing.The stability of the ship has been verified through the calculations of initial stability,static stability,and dynamic stability through the fulfillment of the weather criterion using MAXSURF software.The structural analysis of the sail was carried out in ANSYS static structural module.Several flow simulations were carried out in ANSYS fluent module to predict the thrusts produced by the sails at different apparent wind angles,which would in turn reduce the thrust required from the propeller.In this way,the brake horse powers required for different sail arrangements were analyzed to find out a guideline for this wind propulsion system to generate better powering performances.To consider drift and yaw effect on propulsion system,an MMG mathematical model–based simulation was carried out for different drift angles of motion of the ship considering hard sail–based wind loads.Through these analyses,it has been found out that the hard sail–based wind-assisted propulsion system in some cases have produced a reduction of more than 30%brake power in straight ahead motion and around 20%reduction in case of drifting ships compared to the model having no sails.展开更多
1.Background The use of engineering tools,design,research,and thinking to create environments and capabilities whereby individuals who are currently under-employed or unemployed due to a physical disability(e.g.,amput...1.Background The use of engineering tools,design,research,and thinking to create environments and capabilities whereby individuals who are currently under-employed or unemployed due to a physical disability(e.g.,amputation or spinal cord injury)or neurological difference(e.g.,autism)are enabled to become fully productive and employed members of society has been the implicit goal of decades of research at Vanderbilt University and elsewhere.At Vanderbilt University,progress in these areas has been greatly facilitated by the proximity of the School of Engineering to the world-class Vanderbilt University Medical Center and the resulting close collaboration between engineering and medical researchers.展开更多
Data management experts met on September 21,2020 in Beijing and online at the 2020 National Big Data Standardization Conference and the 7th plenary meeting of the big data working group of National Information Securit...Data management experts met on September 21,2020 in Beijing and online at the 2020 National Big Data Standardization Conference and the 7th plenary meeting of the big data working group of National Information Security Standardization Technical Committee(SAC/TC 28),sharing and exchanging the progress and prospects in the area.展开更多
On 26 July,a parallel session of the Seventh China-Africa People's Forum&the Seventh China-Africa Young Leaders Forum-Forum on Youth Development,Innovation and Entrepreneurship was held in Yiyang.
The fourth issue of iEnergy in 2023 has arrived,with 11 papers published,including 2 news and views,2 highlights,1 letter,3 review articles,and 3 original research articles.The dynamics of contemporary power systems a...The fourth issue of iEnergy in 2023 has arrived,with 11 papers published,including 2 news and views,2 highlights,1 letter,3 review articles,and 3 original research articles.The dynamics of contemporary power systems are undergoing a profound metamorphosis.The once-linear energy flow from centralized sources is giving way to a distributed and diverse energy landscape.展开更多
China helps to diversify Zambia’s energy output to tackle chronic electricity shortages Innocent Gondwe tries to put up a smile as he uses his welding machine anxiously to finish his work in time in order to get paid...China helps to diversify Zambia’s energy output to tackle chronic electricity shortages Innocent Gondwe tries to put up a smile as he uses his welding machine anxiously to finish his work in time in order to get paid,before a scheduled power cut.But he is unable to fully hide the pain in his eyes caused by the frequent power cuts that are a!ecting his business,which solely depends on electricity supply from ZESCO,Zambia’s major power utility company.After dropping out of school,Gondwe went all out to establish himself as an artisan to earn a living in Kalingalinga,one of the slums in Lusaka,Zambia’s capital.展开更多
Uganda launches giant China-constructed hydropower plant to bolster its electricity supply,and also assist South Sudan with theirs Ugandans and South Sudanese have had their lives lit up by the steady flow of electric...Uganda launches giant China-constructed hydropower plant to bolster its electricity supply,and also assist South Sudan with theirs Ugandans and South Sudanese have had their lives lit up by the steady flow of electricity from a massive hydropower infrastructure project,constructed by one of China’s leading contractors.展开更多
There are abound with the deconstruction of classic works in recent years,among which Updike’s Gertrude and Claudius is undoubtedly an impressive one.Updike completed the antecedent part of Shakespeare’s play Hamlt....There are abound with the deconstruction of classic works in recent years,among which Updike’s Gertrude and Claudius is undoubtedly an impressive one.Updike completed the antecedent part of Shakespeare’s play Hamlt.Noticeably,this new prequel of Hamlet,from the mindset of female,takes Queen Gertrude as the narrative center and airs Gertrude’s psychological states to break the confinement of female discourse in Shakespeare’s plays.Hinged on Foucault’s theory of power and discourse,this paper attempts to analyze how Updike manifests women’s endeavors to assert preserve and construct their discourse,break the aphasia and even challenge the voice of male authority by elucidating the interactions between Queen Gertrude and other crucial male roles in the full text in order to navigate readers in-depth to scrutinize the changes of women’s social status in different era.展开更多
As a new branch of efficient and low-cost mechanical energy conversion technology,triboelectric nanogenerator(TENG)is a potential solution to provide a long-term power supply for the Internet of Things(IoT)sensors and...As a new branch of efficient and low-cost mechanical energy conversion technology,triboelectric nanogenerator(TENG)is a potential solution to provide a long-term power supply for the Internet of Things(IoT)sensors and portable electronic devices.However,due to inherent working properties of TENG itself such as extremely high internal impedance,pulse,and alternating current(AC)output,TENG can not directly supply power to loads such as batteries efficiently.Based on these,we describe TENG’s performance from a new perspective of powering ability.It consists of two aspects:the ability to transport charge effectively and the ability to output high power quality current steadily.In order to push forward the developments and applications of TENG,it is necessary to improve its power supply capacity from different perspectives.Fortunately,in recent years,a variety of output signal’s management strategies aiming at effectively managing the generated electricity and significantly improving powering ability of TENG have obtained significantly progress.Herein,this paper discusses the working mechanisms and different load characteristics of TENG at first to clarify the electric performance of TENG.Then,on basis of theoretical analysis,the output signal’s management strategies are elaborated from four aspects:improving the cycle output electricity of TENG,increasing the surface charge density of TENG,improving the power quality of TENG-based energy harvesting system,promoting the application of TENG through integrated circuit(IC)technology and TENG network,and the relevant principles and applications are discussed systematically.Finally,the advantages and disadvantages of the above output signal’s management strategies are summarized and discussed,and the future development of the output signal’s management strategies for TENG is prospected.展开更多
A 320 MW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowe...A 320 MW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowering methods. The power plant repower- ing has been analyzed for three different feed water flow rates： a flow rate equal to the flow rate at the condenser exit in the original plant when it works at nominal load, a flow rate at maximum load, and a flow rate when all the extractions are blocked. For each flow rates, two types of gas turbines have been examined： V94.2 and V94.3A. The effect of a duct burner has then been investigated in each of the above six cases. Steam is produced by a double- pressure heat recovery steam generator （HRSG） with reheat which obtains its required heat from the exhaust gases coming from the gas turbines. The results obtained from modeling and analyzing the energy-exergy of the original steam power plant and the repowered power plant indicate that the maximum efficiency of the repowered power plant is 52.04%. This maximum efficiency occurs when utilizing two V94.3A gas turbines without duct burner in the steam flow rate of the nominal load.展开更多
Space-Based Solar Power(SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply. However, its commercialization...Space-Based Solar Power(SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply. However, its commercialization faces significant obstacles due to the technical challenges of long-distance microwave Wireless Power Transmission(WPT) from geostationary orbit. Even ground-based kilometer-scale WPT experiments remain difficult because of limited testing infrastructure, high costs, and strict electromagnetic wave regulations. Since the 1975 NASA-Raytheon experiment, which successfully recovered 30 kW of power over 1.55 km, there has been little progress in extending the transmission distance or increasing the retrieved power. This study proposes a cost-effective methodology for conducting long-range WPT experiments in constrained environments by utilizing existing infrastructure. A deep space antenna operating at 2.08 GHz with an output power of 2.3 kW and a gain of 55.3 dBi was used as the transmitter. Two test configurations were implemented: a 1.81 km ground-to-air test using an aerostat to elevate the receiver and a 1.82 km ground-to-ground test using a ladder truck positioned on a plateau. The rectenna consists of a lightweight 3×3 patch antenna array(0.9 m × 0.9 m), accompanied by a steering device and LED indicators to verify power reception. The aerostat-based test achieved a power density of 154.6 mW/m2, which corresponds to approximately 6.2% of the theoretical maximum. The performance gap is primarily attributed to near-field interference, detuning of the patch antenna, rectifier mismatch, and alignment issues. These limitations are expected to be mitigated through improved patch antenna fabrication, a transition from GaN to GaAs rectifiers optimized for lower input power, and the implementation of an automated alignment system. With these enhancements, the recovered power is expected to improve by approximately four to five times. The results demonstrate a practical and scalable framework for long-range WPT experiments under constrained conditions and provide key insights for advancing SBSP technology.展开更多
As fundamental economic units,county economies play a crucial role in China's national economic system.However,it remains unclear whether intellectual property rights policies at the county level can promote econo...As fundamental economic units,county economies play a crucial role in China's national economic system.However,it remains unclear whether intellectual property rights policies at the county level can promote economic growth.We used a quasi-natural experiment from the Intellectual Property Powering County Project("the Project")to measure their impact on county economic growth from 2009 to 2020,applying a multi-period diference-in-differences method.County economic growth indicators were measured using Enhanced Vegetation Index-calibrated nighttime light data from the Defense Meteorological Satellite Program and Visible Infrared Imaging Radiometer Suite.The findings demonstrated that the Project promoted economic growth significantly by incentivizing innovation,attracting high-tech and new-tech enterprises,and fostering brand creation.The Project also exhibited significant heterogeneity across districts and counties,along with spillover effects on economic growth in surrounding counties within approximately 80 kilometers.展开更多
An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc...An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.展开更多
文摘China’s Dongfang Electric Machinery successfully completed the manufacturing of the first batch of embedded components for six turbines it is supplying for the Koysha Hydroelectric Dam project in Ethiopia.Transported by land and sea,these parts will arrive on site in three months.Once completed,the power plant will generate more than 6 billion kwh of electricity annually,reducing carbon dioxide emissions by 1 million tonnes per year.
文摘The rapid evolution and expanding scale of AI(artificial intelligence)technologies exert unprecedented energy demands on global electrical grids.Powering computationally intensive tasks such as large-scale AI model training and widespread real-time inference necessitates substantial electricity consumption,presenting a significant challenge to conventional power infrastructure.This paper examines the critical need for a fundamental shift towards smart energy grids in response to AI’s growing energy footprint.It delves into the symbiotic relationship wherein AI acts as a significant energy consumer while offering the intelligence required for dynamic load management,efficient integration of renewable energy sources,and optimized grid operations.We posit that advanced smart grids are indispensable for facilitating AI’s sustainable growth,underscoring this synergy as a pivotal advancement toward a resilient energy future.
文摘16 September 2013, Shenzhen--ZTE today unveiled the world＇s first flexible, reconfigurable terabit router that allows customers to build the highest-performance broadband networks. The terabit router supports the deployment of multiple line cards with processing capabilities of 10 Gbps to 1 Tbps. It also supports the deployment of modules that can scale throughput from 200 Gbps to 18 Tbps. For easy installation in a range of environments, the router interfaces are flexible and the component design is loose-coupled. This allows customers to customize networks to their needs and promotes adaptability, consistency, and continuity.
文摘MORE than 1,000 Ghanaians are benefiting directly by way of jobs from a $600 million Sunon Asogli Thermal Power Plant （Ghana） Limited project - a power generating plant established in the Kpone-Tema metropolis, one of the highly industrialized metropolitan areas in Ghana.
基金Supported by Natural Science Foundation of Hebei Province(E2013204069)Scienceand Technology Research and Development Program of Baoding City(13ZG020+4 种基金13ZF005)Science and Engineering Fund of Agricultural University of Hebei(LG20120204LG201401)College Students’Innovation and Entrepreneurship Fund of Agricultural University of Hebei(201310086011cxzr2014031)~~
文摘In order to meet the self-powered requirement by microelectronic products and micro-electrostatic vibration generator and avoid the environmental pollution caused by waste batteries,many countries have started their researches on piezoelectric power generation based on the researches on the recovery device of rotational energy of piezoelectric effect.The piezoelectric power generation has many advantages compared with other generation patterns.The piezoelectric power generation has become a new field of research.In this study,the piezoelectric vibrators were used to convert energy.According to the requirements by tire pressure alarm system,the energy conversion and storage were researched and analyzed by using the passive sensing device used in automotive inspection.The converted energy was then provided to the alarm,achieving intelligent control and utilization of piezoelectric vibrators.
文摘The wind-assisted propulsion system is becoming one of the most popular and efficient ways to reduce both fuel consumption and carbon dioxide emission from the ships.In this study,several analyses have been carried out on a model of bulk carrier fitted with five rigid sails with a 180°rotating mechanism for maximum usage of wind power and a telescopic reefing mechanism for folding it during berthing.The stability of the ship has been verified through the calculations of initial stability,static stability,and dynamic stability through the fulfillment of the weather criterion using MAXSURF software.The structural analysis of the sail was carried out in ANSYS static structural module.Several flow simulations were carried out in ANSYS fluent module to predict the thrusts produced by the sails at different apparent wind angles,which would in turn reduce the thrust required from the propeller.In this way,the brake horse powers required for different sail arrangements were analyzed to find out a guideline for this wind propulsion system to generate better powering performances.To consider drift and yaw effect on propulsion system,an MMG mathematical model–based simulation was carried out for different drift angles of motion of the ship considering hard sail–based wind loads.Through these analyses,it has been found out that the hard sail–based wind-assisted propulsion system in some cases have produced a reduction of more than 30%brake power in straight ahead motion and around 20%reduction in case of drifting ships compared to the model having no sails.
基金support has been provided by US National Science Foundation(OIA-1936970)a Howard Hughes Medical Institute professorship award.
文摘1.Background The use of engineering tools,design,research,and thinking to create environments and capabilities whereby individuals who are currently under-employed or unemployed due to a physical disability(e.g.,amputation or spinal cord injury)or neurological difference(e.g.,autism)are enabled to become fully productive and employed members of society has been the implicit goal of decades of research at Vanderbilt University and elsewhere.At Vanderbilt University,progress in these areas has been greatly facilitated by the proximity of the School of Engineering to the world-class Vanderbilt University Medical Center and the resulting close collaboration between engineering and medical researchers.
文摘Data management experts met on September 21,2020 in Beijing and online at the 2020 National Big Data Standardization Conference and the 7th plenary meeting of the big data working group of National Information Security Standardization Technical Committee(SAC/TC 28),sharing and exchanging the progress and prospects in the area.
文摘On 26 July,a parallel session of the Seventh China-Africa People's Forum&the Seventh China-Africa Young Leaders Forum-Forum on Youth Development,Innovation and Entrepreneurship was held in Yiyang.
文摘The fourth issue of iEnergy in 2023 has arrived,with 11 papers published,including 2 news and views,2 highlights,1 letter,3 review articles,and 3 original research articles.The dynamics of contemporary power systems are undergoing a profound metamorphosis.The once-linear energy flow from centralized sources is giving way to a distributed and diverse energy landscape.
文摘China helps to diversify Zambia’s energy output to tackle chronic electricity shortages Innocent Gondwe tries to put up a smile as he uses his welding machine anxiously to finish his work in time in order to get paid,before a scheduled power cut.But he is unable to fully hide the pain in his eyes caused by the frequent power cuts that are a!ecting his business,which solely depends on electricity supply from ZESCO,Zambia’s major power utility company.After dropping out of school,Gondwe went all out to establish himself as an artisan to earn a living in Kalingalinga,one of the slums in Lusaka,Zambia’s capital.
文摘Uganda launches giant China-constructed hydropower plant to bolster its electricity supply,and also assist South Sudan with theirs Ugandans and South Sudanese have had their lives lit up by the steady flow of electricity from a massive hydropower infrastructure project,constructed by one of China’s leading contractors.
文摘There are abound with the deconstruction of classic works in recent years,among which Updike’s Gertrude and Claudius is undoubtedly an impressive one.Updike completed the antecedent part of Shakespeare’s play Hamlt.Noticeably,this new prequel of Hamlet,from the mindset of female,takes Queen Gertrude as the narrative center and airs Gertrude’s psychological states to break the confinement of female discourse in Shakespeare’s plays.Hinged on Foucault’s theory of power and discourse,this paper attempts to analyze how Updike manifests women’s endeavors to assert preserve and construct their discourse,break the aphasia and even challenge the voice of male authority by elucidating the interactions between Queen Gertrude and other crucial male roles in the full text in order to navigate readers in-depth to scrutinize the changes of women’s social status in different era.
基金funded by the National Key R&D Project from Minister of Science and Technology(No.2021YFA1201602)the National Natural Science Foundation of China(Nos.52172203 and U21A20175).
文摘As a new branch of efficient and low-cost mechanical energy conversion technology,triboelectric nanogenerator(TENG)is a potential solution to provide a long-term power supply for the Internet of Things(IoT)sensors and portable electronic devices.However,due to inherent working properties of TENG itself such as extremely high internal impedance,pulse,and alternating current(AC)output,TENG can not directly supply power to loads such as batteries efficiently.Based on these,we describe TENG’s performance from a new perspective of powering ability.It consists of two aspects:the ability to transport charge effectively and the ability to output high power quality current steadily.In order to push forward the developments and applications of TENG,it is necessary to improve its power supply capacity from different perspectives.Fortunately,in recent years,a variety of output signal’s management strategies aiming at effectively managing the generated electricity and significantly improving powering ability of TENG have obtained significantly progress.Herein,this paper discusses the working mechanisms and different load characteristics of TENG at first to clarify the electric performance of TENG.Then,on basis of theoretical analysis,the output signal’s management strategies are elaborated from four aspects:improving the cycle output electricity of TENG,increasing the surface charge density of TENG,improving the power quality of TENG-based energy harvesting system,promoting the application of TENG through integrated circuit(IC)technology and TENG network,and the relevant principles and applications are discussed systematically.Finally,the advantages and disadvantages of the above output signal’s management strategies are summarized and discussed,and the future development of the output signal’s management strategies for TENG is prospected.
文摘A 320 MW old steam power plant has been chosen for repowering in this paper. Considering the technical conditions and working life of the power plant, the full repowering method has been selected from different repowering methods. The power plant repower- ing has been analyzed for three different feed water flow rates： a flow rate equal to the flow rate at the condenser exit in the original plant when it works at nominal load, a flow rate at maximum load, and a flow rate when all the extractions are blocked. For each flow rates, two types of gas turbines have been examined： V94.2 and V94.3A. The effect of a duct burner has then been investigated in each of the above six cases. Steam is produced by a double- pressure heat recovery steam generator （HRSG） with reheat which obtains its required heat from the exhaust gases coming from the gas turbines. The results obtained from modeling and analyzing the energy-exergy of the original steam power plant and the repowered power plant indicate that the maximum efficiency of the repowered power plant is 52.04%. This maximum efficiency occurs when utilizing two V94.3A gas turbines without duct burner in the steam flow rate of the nominal load.
文摘Space-Based Solar Power(SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply. However, its commercialization faces significant obstacles due to the technical challenges of long-distance microwave Wireless Power Transmission(WPT) from geostationary orbit. Even ground-based kilometer-scale WPT experiments remain difficult because of limited testing infrastructure, high costs, and strict electromagnetic wave regulations. Since the 1975 NASA-Raytheon experiment, which successfully recovered 30 kW of power over 1.55 km, there has been little progress in extending the transmission distance or increasing the retrieved power. This study proposes a cost-effective methodology for conducting long-range WPT experiments in constrained environments by utilizing existing infrastructure. A deep space antenna operating at 2.08 GHz with an output power of 2.3 kW and a gain of 55.3 dBi was used as the transmitter. Two test configurations were implemented: a 1.81 km ground-to-air test using an aerostat to elevate the receiver and a 1.82 km ground-to-ground test using a ladder truck positioned on a plateau. The rectenna consists of a lightweight 3×3 patch antenna array(0.9 m × 0.9 m), accompanied by a steering device and LED indicators to verify power reception. The aerostat-based test achieved a power density of 154.6 mW/m2, which corresponds to approximately 6.2% of the theoretical maximum. The performance gap is primarily attributed to near-field interference, detuning of the patch antenna, rectifier mismatch, and alignment issues. These limitations are expected to be mitigated through improved patch antenna fabrication, a transition from GaN to GaAs rectifiers optimized for lower input power, and the implementation of an automated alignment system. With these enhancements, the recovered power is expected to improve by approximately four to five times. The results demonstrate a practical and scalable framework for long-range WPT experiments under constrained conditions and provide key insights for advancing SBSP technology.
基金support from the China National Social Science Foundation (No.23BJY216)the Major Project of the key research institutes of Chinese Ministry of Education (No.22JJD790051)+1 种基金the Key Project of Social Science Foundation of Fujian Province (No.FJ2022A011)the Fundamental Research Funds for the Central Universities (No.20720191070).
文摘As fundamental economic units,county economies play a crucial role in China's national economic system.However,it remains unclear whether intellectual property rights policies at the county level can promote economic growth.We used a quasi-natural experiment from the Intellectual Property Powering County Project("the Project")to measure their impact on county economic growth from 2009 to 2020,applying a multi-period diference-in-differences method.County economic growth indicators were measured using Enhanced Vegetation Index-calibrated nighttime light data from the Defense Meteorological Satellite Program and Visible Infrared Imaging Radiometer Suite.The findings demonstrated that the Project promoted economic growth significantly by incentivizing innovation,attracting high-tech and new-tech enterprises,and fostering brand creation.The Project also exhibited significant heterogeneity across districts and counties,along with spillover effects on economic growth in surrounding counties within approximately 80 kilometers.
基金Open access funding provided by FCT|FCCN(b-on)the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020.
文摘An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.
