In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the...In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the networks presents uneven distribution.To achieve energy balance in networks,an energy consumption balancing optimization algorithm of LEO networks based on distance energy factor(DEF)is proposed.The DEF is defined as the function of the inter-satellite link dis-tance and the cumulative network energy consumption ratio.According to the minimum sum of DEF on inter-satellite links,an energy consumption balancing algorithm based on DEF is pro-posed,which can realize dynamic traffic transmission optimiza-tion of multiple traffic services.It can effectively reduce the energy consumption pressure of core nodes with high energy consumption in the network,make full use of idle nodes with low energy consumption,and optimize the energy consumption dis-tribution of the whole network according to the continuous itera-tions of each traffic service flow.Simulation results show that,compared with the traditional shortest path algorithm,the pro-posed method can improve the balancing performance of nodes by 75%under certain traffic pressure,and realize the optimiza-tion of energy consumption balancing of the whole network.展开更多
Bohai Rim region is an important economic development area and a large carbon emission area in China.It is of great significance to explore the total factor energy efficiency and its influencing factors for the low ca...Bohai Rim region is an important economic development area and a large carbon emission area in China.It is of great significance to explore the total factor energy efficiency and its influencing factors for the low carbon transformation and high-quality development of the Bohai Rim region.Based on the total factor energy efficiency framework,the DDF-DEA model was used to calculate the total factor energy efficiency,and the internal and external differences of the total factor energy efficiency were further analyzed.The internal and external influencing factors were determined by ML index method and classical endogenous growth theory,and then the Tobit panel model was used to empirically analyze the action mechanism of all influencing factors of total factor energy efficiency in the Bohai Rim region.The results show that the pure technical efficiency,scale efficiency and technological progress among the internal influencing factors contribute to the improvement of energy efficiency in the Bohai Rim region.Industrial structure,industrial internal structure and ownership structure inhibit the improvement of energy efficiency.Energy consumption structure and energy endowment also have a negative impact on energy efficiency.Therefore,measures such as promoting technological progress,adjusting economic structure and optimizing energy structure will effectively improve total factor energy efficiency in the Bohai Rim region.展开更多
Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthq...Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.展开更多
The paper demonstrates how electromagnetic processing of materials(EPM)provides significant opportunities for saving primary energy and reducing carbon emissions in industrial thermal processes.Potentially electricity...The paper demonstrates how electromagnetic processing of materials(EPM)provides significant opportunities for saving primary energy and reducing carbon emissions in industrial thermal processes.Potentially electricity can replace up to 100%of other energy carriers currently used for process heat.For the time horizon from now to the year 2050 a transition scenario is developed and described.In this scenario the industrial processes are gradually switched from the actual situation to a situation with 100%electrically operated industrial processes.The developed scenarios take into account the most energy intensive industrial thermal processes,which could be replaced by electrothermal technologies and offer obviously the biggest future potential in terms of saving of primary energy and reducing of carbon emissions.As the average primary energy factor(PEF)gradually decreases from 2.5 currently,to 1 for a 100%renewable electricity system,the benefits of EPM will gradually increase.For each step in the development of the PEF the annual primary energy savings and annual reductions in greenhouse gas emissions are calculated and described in this paper.展开更多
In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission （ET） that ensures each forwarding node is not only farther from the s...In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission （ET） that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.展开更多
Energy plays an important role in the economic life. With the rapid development of economy, the constraint of energy on the sustainable development of economy is becoming more and more obvious. This paper just Studies...Energy plays an important role in the economic life. With the rapid development of economy, the constraint of energy on the sustainable development of economy is becoming more and more obvious. This paper just Studies the factors influencing energy efficiency of China and the relationship between energy efficiency and China＇s economic： growth. By using time series multivariable linear regression methods with China＇s relevant data from 1953 to 2006, this paper constructs the regression model to analyze the factors that would impact energy, efficiency. After that, a regression model of China＇s real output to capital, labor and energy e lficiency is conducted to estimate the marginal contribution of every factor to the real output to prove the fundamental influence of energy efficiency to the economic growth. In the end, some policies and recommendations are also put forward in order to improve the energy efficiency; of China.展开更多
A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal...A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal components,electric motor,system efficiency optimization models are developed.According to the target of instantaneous optimization of system efficiency,operating ranges of each mode of power-train are determined,and the corresponding energy management strategies are established.The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy,and keep battery state of charge（SOC）change in a reasonable variation range.展开更多
1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems ...1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or C<sub>f</sub>) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.展开更多
Effects of Mn content on mechanical properties of FeCoCrNiMn_(x)(0≤x≤0.3)high-entropy alloys(HEAs)are investigated via first-prmciples calculations combining EMTO-CPA method.Related physical parameters,including lat...Effects of Mn content on mechanical properties of FeCoCrNiMn_(x)(0≤x≤0.3)high-entropy alloys(HEAs)are investigated via first-prmciples calculations combining EMTO-CPA method.Related physical parameters,including lattice constant.elastic constants,elastic modulus,Pugh’s ratio,anisotropy factors,Poisson’s ratio,Cauchy pressure,Vickers hardness,yield strength,and energy factor,are calculated as a function of Mn content.The results show that the resistances to bulk,elastic,and shear deformation decrease with increasing Mn content.Pugh’s ratio B/G indicates that the ductility of FeCoCrNiMn_(x) HEAs has a remarkable reduction between 22 and 24% of Mn content.Meanwhile,Cauchy pressure suggests that the atomic bonding transforms from metallic to directional characteristic from 22 to 24% of Mn content.Vickers hardness and yield strength of FeCoCrNiMn HEA are intrinsically larger than those of FeCoCrNi HEA.Dislocation nucleation easily occurs in FeCoCrNiMn HE A compared to FeCoCrNi HEA,and large dislocation width in FeCoCrNiMnO_(2) HE A results in low stacking-fault energy,which easily induces twinning deformation.This work provides a valuable msieht for further theoretical and experimental study on the mechanical properties of FeCoCrNiMn_(x)(0≤x≤0.3)HEAs.展开更多
This research focuses on improving the Harris’Hawks Optimization algorithm(HHO)by tackling several of its shortcomings,including insufficient population diversity,an imbalance in exploration vs.exploitation,and a lac...This research focuses on improving the Harris’Hawks Optimization algorithm(HHO)by tackling several of its shortcomings,including insufficient population diversity,an imbalance in exploration vs.exploitation,and a lack of thorough exploitation depth.To tackle these shortcomings,it proposes enhancements from three distinct perspectives:an initialization technique for populations grounded in opposition-based learning,a strategy for updating escape energy factors to improve the equilibrium between exploitation and exploration,and a comprehensive exploitation approach that utilizes variable neighborhood search along with mutation operators.The effectiveness of the Improved Harris Hawks Optimization algorithm(IHHO)is assessed by comparing it to five leading algorithms across 23 benchmark test functions.Experimental findings indicate that the IHHO surpasses several contemporary algorithms its problem-solving capabilities.Additionally,this paper introduces a feature selection method leveraging the IHHO algorithm(IHHO-FS)to address challenges such as low efficiency in feature selection and high computational costs(time to find the optimal feature combination and model response time)associated with high-dimensional datasets.Comparative analyses between IHHO-FS and six other advanced feature selection methods are conducted across eight datasets.The results demonstrate that IHHO-FS significantly reduces the computational costs associated with classification models by lowering data dimensionality,while also enhancing the efficiency of feature selection.Furthermore,IHHO-FS shows strong competitiveness relative to numerous algorithms.展开更多
Modern energy services are a necessary prerequisite for human well-being and the economic development of a country. Access to modern energy is essential for the supply of clean water, hygiene and health, and for the p...Modern energy services are a necessary prerequisite for human well-being and the economic development of a country. Access to modern energy is essential for the supply of clean water, hygiene and health, and for the provision of reliable and efficient lighting, heating, cooking, and mechanical power. It seems clear, therefore, that the energy factor and its availability, the demand for which is growing, must be ensured over time. Moreover, considering that the world population will significantly increase in coming decades and, legitimately, all of these individuals want access to sources of energy for a better quality of life. The patterns of consumption most commonly used nowadays are expensive and highly polluting, but, most importantly, now they are almost completely exhausted. Therefore, research has to find sources of ＂alternative＂ and renewable energy in order to sustain the continuously growing global demand for energy. It is necessary, therefore, to develop and improve policies in order to change current consumption patterns, while strengthening approaches and strategies for sustainable models, applying incentives for good behavior and penalizing waste, and promoting the empowerment of producers. This paper concerns this sector and aims to highlight innovation in bioclimatic and eco-friendly buildings.展开更多
After optimizing the compressor design,condenser tube diameter,and tube row arrangement,air supply volumetric flow rate,and refrigerant charge of the domestic dehumidifier.The optimized design schemes were obtained fr...After optimizing the compressor design,condenser tube diameter,and tube row arrangement,air supply volumetric flow rate,and refrigerant charge of the domestic dehumidifier.The optimized design schemes were obtained from the original combinations by non-dominated sorting,and the optimized design schemes were experimentally verified under three environmental conditions according to the test method of T/CAS 342-2020 to obtain a complete idea of dehumidifier multi-component improvement.The results show that the dehumidifying capacity of Scheme 5 is slightly increased by 2.5%at 27℃/60%RH,and its energy factor is significantly increased by 24.6%.When the air supply volumetric flow rate was increased from 210 to 268 m^(3)·h^(-1),the air supply temperature was reduced by 1.7℃,improving comfort.Under environmental conditions with higher dehumidification demand,i.e.,at 35℃/90%RH,the energy factor of Scheme 4 can reach 4.3 L·kW^(-1)·h^(-1),which is 34.4%higher than the original scheme,and the gap is further widened.The application of the 5 mm tube diameter condenser in dehumidifiers reduces the amount of refrigerant charge by 25.9%,reduces the cost by 7.5%,and strengthens the heat transfer effect and the homogeneity of the two-phase mixing,which shows the great application potential.展开更多
Objective The aim of this study was to investigate the energy deposition in the target area of high intensity focused ultrasound （HIFU） with ultrasound-guided intra-hysteromyoma injection of ethyl alcohol absolute M...Objective The aim of this study was to investigate the energy deposition in the target area of high intensity focused ultrasound （HIFU） with ultrasound-guided intra-hysteromyoma injection of ethyl alcohol absolute Methods Eighty patients with hysteromyomas were randomly divided into two groups： group HIFU （group H） and group HIFU combined with ullrasound-guided inlra-hysteromyoma injectionn of ethyl alcohol absolute （group E ＋ H）. Patients in group E ＋ H received an ullrasound-guided injection of absolute ethyl alcohol 1 h before HIFU treatment. The irradiation time, irradiation dose, energy efficiency factor （radiation energy required for ablation of a myoma per unit of volume）, grey variation, pain score, and adverse reactions were compared between the two groups. An independent sample t-test was used with a two- tailed P-value of 〈 0.05. Results The irradiation time, irradiation dose, and energy efficiency factor were significantly lower in group E ＋ H than those in group H （P 〈 0.05）. The hysteromyomas of patients in group E＋H appeared as dominantly hyperechoic masses, and those of patients in group H appeared as hyperechoic tissue （non- mass）. The incidence of adverse reactions and pain score were higher in group H than those in group E ＋ H （P 〈 0.05）. Conclusion Ultrasound-guided inlra-hysteromyoma injection of ethyl alcohol absolute can enhance the energy deposition of HIFU in the uterine fibroids, improve the treatment efficiency, shorten the treatment time, reduce the treatment dose, and reduce the pain and complications for the patients.展开更多
A precise energy conversion factor is required to define the impact of greenhouse gas emissions by gasoline-powered vehi-cles and policies that will guide the application of future eco-innovations.The current energy c...A precise energy conversion factor is required to define the impact of greenhouse gas emissions by gasoline-powered vehi-cles and policies that will guide the application of future eco-innovations.The current energy conversion factor adopted by many countries is based on the Willans line approach,initially proposed in 1888 for steam engines,later adapted for internal combustion engines.The actual energy conversion factor,which defines the energy conversion for drivers in real traffic,is missing.In this article,eight world-class engines are tested in an engine bench for the acquisition of specific fuel consumption 3D maps.Then,their energy conversion factors,calculated by dividing the energy output by the energy input,are simulated in real and urban traffic,acquired according to the real driving emissions(RDE)cycle.In addition,a reference vehicle is instrumented to measure the energy input(fuel flow)and the energy output(mechanical energy in the half axles)under the same RDE cycle standards.The results of both procedures are very similar,respectively,0.405±0.04 L/kWh for the simulation based on eight benchmark engines,and 0.392±0.04 L/kWh for the reference vehicle driven in RDE traffic conditions,with a 95%confidence interval.For turbocharged engines,the factor attained by the simulation is 0.395±0.04 L/kWh.The values of the energy conversion factor for gasoline engines got in this research are higher than those obtained through the Willans line approach,suggesting a new standard value of 0.405 L/kWh,replacing the current 0.264 L/kWh.It could substantially change the greenhouse gas emissions in a tank-to-wheel approach for the entire vehicle and add-on eco-innovations.展开更多
By modeling metal as a special piezoelectric material with extremely small piezoelectricity and extremely large permittivity,we have obtained the analytical solutions for an interracial permeable crack in metal/piezoe...By modeling metal as a special piezoelectric material with extremely small piezoelectricity and extremely large permittivity,we have obtained the analytical solutions for an interracial permeable crack in metal/piezoelectric bimaterials by means of the generalized Stroh formalism.The analysis shows that the stress fields near a permeable interracial crack tip are usually with three types of singularities:r^-1/2±iεand r^-1/2.Further numerical calculation on the oscillatory indexεare given for 28 types of metal/piezoelectric bimaterials combined by seven commercial piezoelectric materials:PZT-4,BaTiO3,PZT-5H,PZT-6B,PZT-7A,P-7 and PZT-PIC 151 and four metals:copper,silver,lead and aluminum,respectively.The explicit expressions of the crack tip energy release rate(ERR)and the crack tip generalized stress intensity factors(GSIF)are obtained.It is found that both the ERR and GSIF are independent of the electric displacement loading,although they seriously depends on the mechanical loadings.展开更多
This study employed a difference-in-differences design to assess the effect of marketbased environmental regulation on green total factor energy efficiency(GTFEE)in a quasi-natural experiment that investigated China&#...This study employed a difference-in-differences design to assess the effect of marketbased environmental regulation on green total factor energy efficiency(GTFEE)in a quasi-natural experiment that investigated China's carbon emissions trading scheme(ETS).The empirical results show that ETS had a positive effect on GTFEE.A series of robustness tests revealed that the results were robust.Potential mechanisms through which ETS can improve GTFEE include the promotion of technological innovation and the upgrading of industrial structure.The positive effects varied in different cities and diferent regions-the result was pronounced in eastern China and developed cities,but it was insignificant in central and western areas and developing cities.This study confirms the satisfactory performance of China's ETS in improving GTFEE,and this is relevant for other emerging countries.展开更多
In order to calculate the stress intensity factor(SIF) of crack tips in two-dimensional cracks from the viewpoint of strain energy density, a procedure to use the strain energy density factor to calculate the SIF is p...In order to calculate the stress intensity factor(SIF) of crack tips in two-dimensional cracks from the viewpoint of strain energy density, a procedure to use the strain energy density factor to calculate the SIF is proposed. In this paper, the procedure is presented to calculate the SIF of crack tips in mode I cracks, mode II cracks and I+II mixed mode cracks. Meanwhile, the results are compared to those calculated by traditional approaches or other approaches based on strain energy density and verified by theoretical solutions. Furthermore, the effect of mesh density near the crack tip is discussed, and the proper location where the strain energy density factor is calculated is also studied. The results show that the SIF calculated by this procedure is close to not only those calculated by other approaches but also the theoretical solutions, thus it is capable of achieving accurate results.Besides, the mesh density around the crack tip should meet such requirements that, in the circular area created, the first layer of singular elements should have a radius about 0.05 mm and each element has a circumferential directional meshing angle to be15°–20°. Furthermore, for a single element around the crack tip, the strain energy density factor is suggested to be calculated in the location where half of the sector element's radius from the crack tip.展开更多
The size reduction of atomic clocks is a long-standing research issue.Many atomic clocks such as passive hydrogen masers(PHMs)and compact rubidium masers(CRMs)use iris-loaded resonance cavities(IRCs)as their microwave...The size reduction of atomic clocks is a long-standing research issue.Many atomic clocks such as passive hydrogen masers(PHMs)and compact rubidium masers(CRMs)use iris-loaded resonance cavities(IRCs)as their microwave cavities because they can dramatically reduce the radical sizes of the atomic clocks.In this paper,the electromagnetic characteristic of the IRC is investigated by a theoretical model based on electromagnetic field theory.The formulas to calculate the resonance frequency,quality factor,and magnetic energy filling factor are presented.The relationship between the IRC structure and its electromagnetic characteristic is clarified.The theoretical calculation results accord well with the electromagnetic software simulations and experimental results.The results in this paper should be helpful in understanding the physical mechanism of the IRC and designing the atomic clocks.展开更多
The torsional impact response of a penny-shaped crack in a nonhomogeneous strip is considered. The shear modulus is assumed to be functionally graded such that the mathematics is tractable. Laplace and Hankel transfor...The torsional impact response of a penny-shaped crack in a nonhomogeneous strip is considered. The shear modulus is assumed to be functionally graded such that the mathematics is tractable. Laplace and Hankel transforms were used to reduce the problem to solving a Fredholm integral equation. The crack tip stress field is obtained by considering the asymptotic behavior of Bessel function. Explicit expressions of both the dynamic stress intensity factor and the energy density factor were derived.And it is shown that, as crack driving force, they are equivalent for the present crack problem. Investigated are the effects of material nonhomogeneity and (strip's) highness on the dynamic fracture behavior. Numerical results reveal that the peak of the dynamic stress intensity factor can be suppressed by increasing the nonhomogeneity parameter of the shear modulus, and that the dynamic behavior varies little with the adjusting of the strip's highness.展开更多
With the background of offshore wind energy projects, this paper studies aerodynamic performance and geometric characteristics of large capacity wind turbine rotors （1 to 10 MW）, and the main characteristic paramete...With the background of offshore wind energy projects, this paper studies aerodynamic performance and geometric characteristics of large capacity wind turbine rotors （1 to 10 MW）, and the main characteristic parameters such as the rated wind speed, blade tip speed, and rotor solidity. We show that the essential criterion of a high- performance wind turbine is a highest possible annual usable energy pattern factor and a smallest possible dimension, capturing the maximum wind energy and producing the maximum annual power. The influence of the above-mentioned three parameters on the pattern factor and rotor geometry of wind turbine operated in China＇s offshore meteoro- logical environment is investigated. The variation patterns of aerodynamic and geometric parameters are obtained, analyzed, and compared with each other. The present method for aerodynamic analysis and its results can form a basis for evaluating aerodynamic performance of large-scale offshore wind turbine rotors.展开更多
基金supported by the National Key Research and Development Program(2021YFB2900604).
文摘In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the networks presents uneven distribution.To achieve energy balance in networks,an energy consumption balancing optimization algorithm of LEO networks based on distance energy factor(DEF)is proposed.The DEF is defined as the function of the inter-satellite link dis-tance and the cumulative network energy consumption ratio.According to the minimum sum of DEF on inter-satellite links,an energy consumption balancing algorithm based on DEF is pro-posed,which can realize dynamic traffic transmission optimiza-tion of multiple traffic services.It can effectively reduce the energy consumption pressure of core nodes with high energy consumption in the network,make full use of idle nodes with low energy consumption,and optimize the energy consumption dis-tribution of the whole network according to the continuous itera-tions of each traffic service flow.Simulation results show that,compared with the traditional shortest path algorithm,the pro-posed method can improve the balancing performance of nodes by 75%under certain traffic pressure,and realize the optimiza-tion of energy consumption balancing of the whole network.
基金supported by the National Natural Science Foundation of China under Grant 71804089the Humanities and Social Sciences Youth Foundation of Ministry of Education of China under Grants 18YJCZH034 and 19YJC790128+3 种基金the Jiangsu Postdoctoral Research Foundation underGrant 2018K195C,the Natural Science Foundation of Shandong Province in China under Grant ZR2020QG054the Graduate Education Quality Improvement Project of Shandong Province,China under Grants SDYKC19180 and SDYAL19180The project number of“The quality course in Financial Statistics”is SDYKC19180The project number of“Financial Literacy Oriented Case Library of Derivative Financial Instruments Teaching”is SDYAL19180.
文摘Bohai Rim region is an important economic development area and a large carbon emission area in China.It is of great significance to explore the total factor energy efficiency and its influencing factors for the low carbon transformation and high-quality development of the Bohai Rim region.Based on the total factor energy efficiency framework,the DDF-DEA model was used to calculate the total factor energy efficiency,and the internal and external differences of the total factor energy efficiency were further analyzed.The internal and external influencing factors were determined by ML index method and classical endogenous growth theory,and then the Tobit panel model was used to empirically analyze the action mechanism of all influencing factors of total factor energy efficiency in the Bohai Rim region.The results show that the pure technical efficiency,scale efficiency and technological progress among the internal influencing factors contribute to the improvement of energy efficiency in the Bohai Rim region.Industrial structure,industrial internal structure and ownership structure inhibit the improvement of energy efficiency.Energy consumption structure and energy endowment also have a negative impact on energy efficiency.Therefore,measures such as promoting technological progress,adjusting economic structure and optimizing energy structure will effectively improve total factor energy efficiency in the Bohai Rim region.
文摘Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.
文摘The paper demonstrates how electromagnetic processing of materials(EPM)provides significant opportunities for saving primary energy and reducing carbon emissions in industrial thermal processes.Potentially electricity can replace up to 100%of other energy carriers currently used for process heat.For the time horizon from now to the year 2050 a transition scenario is developed and described.In this scenario the industrial processes are gradually switched from the actual situation to a situation with 100%electrically operated industrial processes.The developed scenarios take into account the most energy intensive industrial thermal processes,which could be replaced by electrothermal technologies and offer obviously the biggest future potential in terms of saving of primary energy and reducing of carbon emissions.As the average primary energy factor(PEF)gradually decreases from 2.5 currently,to 1 for a 100%renewable electricity system,the benefits of EPM will gradually increase.For each step in the development of the PEF the annual primary energy savings and annual reductions in greenhouse gas emissions are calculated and described in this paper.
基金Supported by the National Natural Science Foun-dation of China (60572049) the Natural Science Foundation ofHubei Province of China (2005ABA264)
文摘In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission （ET） that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.
文摘Energy plays an important role in the economic life. With the rapid development of economy, the constraint of energy on the sustainable development of economy is becoming more and more obvious. This paper just Studies the factors influencing energy efficiency of China and the relationship between energy efficiency and China＇s economic： growth. By using time series multivariable linear regression methods with China＇s relevant data from 1953 to 2006, this paper constructs the regression model to analyze the factors that would impact energy, efficiency. After that, a regression model of China＇s real output to capital, labor and energy e lficiency is conducted to estimate the marginal contribution of every factor to the real output to prove the fundamental influence of energy efficiency to the economic growth. In the end, some policies and recommendations are also put forward in order to improve the energy efficiency; of China.
基金Supported by the National Science and Technology Support Program(2013BAG12B01)Foundational and Advanced Research Program General Project of Chongqing City(cstc2013jcyjjq60002)
文摘A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal components,electric motor,system efficiency optimization models are developed.According to the target of instantaneous optimization of system efficiency,operating ranges of each mode of power-train are determined,and the corresponding energy management strategies are established.The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy,and keep battery state of charge（SOC）change in a reasonable variation range.
文摘1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or C<sub>f</sub>) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.
基金financially supported by the National Natural Science Foundation of China(No.51501060)China Postdoctoral Science Foundation(No.2018M642973)+5 种基金the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body at Hunan University(No.31875004)the Key Laboratory of Guangdong Regular Higher Education(No.2017KSYS012)the Foshan Key Technology Project(No.1920001000409)the Guangzhou Technical Project(No.201704030113)the Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110274)the Foshan University Scientifi c Research Project(Nos.CGG07257 and BGH206017)。
文摘Effects of Mn content on mechanical properties of FeCoCrNiMn_(x)(0≤x≤0.3)high-entropy alloys(HEAs)are investigated via first-prmciples calculations combining EMTO-CPA method.Related physical parameters,including lattice constant.elastic constants,elastic modulus,Pugh’s ratio,anisotropy factors,Poisson’s ratio,Cauchy pressure,Vickers hardness,yield strength,and energy factor,are calculated as a function of Mn content.The results show that the resistances to bulk,elastic,and shear deformation decrease with increasing Mn content.Pugh’s ratio B/G indicates that the ductility of FeCoCrNiMn_(x) HEAs has a remarkable reduction between 22 and 24% of Mn content.Meanwhile,Cauchy pressure suggests that the atomic bonding transforms from metallic to directional characteristic from 22 to 24% of Mn content.Vickers hardness and yield strength of FeCoCrNiMn HEA are intrinsically larger than those of FeCoCrNi HEA.Dislocation nucleation easily occurs in FeCoCrNiMn HE A compared to FeCoCrNi HEA,and large dislocation width in FeCoCrNiMnO_(2) HE A results in low stacking-fault energy,which easily induces twinning deformation.This work provides a valuable msieht for further theoretical and experimental study on the mechanical properties of FeCoCrNiMn_(x)(0≤x≤0.3)HEAs.
基金supported by the National Natural Science Foundation of China(grant number 62073330)constituted a segment of a project associated with the School of Computer Science and Information Engineering at Harbin Normal University。
文摘This research focuses on improving the Harris’Hawks Optimization algorithm(HHO)by tackling several of its shortcomings,including insufficient population diversity,an imbalance in exploration vs.exploitation,and a lack of thorough exploitation depth.To tackle these shortcomings,it proposes enhancements from three distinct perspectives:an initialization technique for populations grounded in opposition-based learning,a strategy for updating escape energy factors to improve the equilibrium between exploitation and exploration,and a comprehensive exploitation approach that utilizes variable neighborhood search along with mutation operators.The effectiveness of the Improved Harris Hawks Optimization algorithm(IHHO)is assessed by comparing it to five leading algorithms across 23 benchmark test functions.Experimental findings indicate that the IHHO surpasses several contemporary algorithms its problem-solving capabilities.Additionally,this paper introduces a feature selection method leveraging the IHHO algorithm(IHHO-FS)to address challenges such as low efficiency in feature selection and high computational costs(time to find the optimal feature combination and model response time)associated with high-dimensional datasets.Comparative analyses between IHHO-FS and six other advanced feature selection methods are conducted across eight datasets.The results demonstrate that IHHO-FS significantly reduces the computational costs associated with classification models by lowering data dimensionality,while also enhancing the efficiency of feature selection.Furthermore,IHHO-FS shows strong competitiveness relative to numerous algorithms.
文摘Modern energy services are a necessary prerequisite for human well-being and the economic development of a country. Access to modern energy is essential for the supply of clean water, hygiene and health, and for the provision of reliable and efficient lighting, heating, cooking, and mechanical power. It seems clear, therefore, that the energy factor and its availability, the demand for which is growing, must be ensured over time. Moreover, considering that the world population will significantly increase in coming decades and, legitimately, all of these individuals want access to sources of energy for a better quality of life. The patterns of consumption most commonly used nowadays are expensive and highly polluting, but, most importantly, now they are almost completely exhausted. Therefore, research has to find sources of ＂alternative＂ and renewable energy in order to sustain the continuously growing global demand for energy. It is necessary, therefore, to develop and improve policies in order to change current consumption patterns, while strengthening approaches and strategies for sustainable models, applying incentives for good behavior and penalizing waste, and promoting the empowerment of producers. This paper concerns this sector and aims to highlight innovation in bioclimatic and eco-friendly buildings.
文摘After optimizing the compressor design,condenser tube diameter,and tube row arrangement,air supply volumetric flow rate,and refrigerant charge of the domestic dehumidifier.The optimized design schemes were obtained from the original combinations by non-dominated sorting,and the optimized design schemes were experimentally verified under three environmental conditions according to the test method of T/CAS 342-2020 to obtain a complete idea of dehumidifier multi-component improvement.The results show that the dehumidifying capacity of Scheme 5 is slightly increased by 2.5%at 27℃/60%RH,and its energy factor is significantly increased by 24.6%.When the air supply volumetric flow rate was increased from 210 to 268 m^(3)·h^(-1),the air supply temperature was reduced by 1.7℃,improving comfort.Under environmental conditions with higher dehumidification demand,i.e.,at 35℃/90%RH,the energy factor of Scheme 4 can reach 4.3 L·kW^(-1)·h^(-1),which is 34.4%higher than the original scheme,and the gap is further widened.The application of the 5 mm tube diameter condenser in dehumidifiers reduces the amount of refrigerant charge by 25.9%,reduces the cost by 7.5%,and strengthens the heat transfer effect and the homogeneity of the two-phase mixing,which shows the great application potential.
文摘Objective The aim of this study was to investigate the energy deposition in the target area of high intensity focused ultrasound （HIFU） with ultrasound-guided intra-hysteromyoma injection of ethyl alcohol absolute Methods Eighty patients with hysteromyomas were randomly divided into two groups： group HIFU （group H） and group HIFU combined with ullrasound-guided inlra-hysteromyoma injectionn of ethyl alcohol absolute （group E ＋ H）. Patients in group E ＋ H received an ullrasound-guided injection of absolute ethyl alcohol 1 h before HIFU treatment. The irradiation time, irradiation dose, energy efficiency factor （radiation energy required for ablation of a myoma per unit of volume）, grey variation, pain score, and adverse reactions were compared between the two groups. An independent sample t-test was used with a two- tailed P-value of 〈 0.05. Results The irradiation time, irradiation dose, and energy efficiency factor were significantly lower in group E ＋ H than those in group H （P 〈 0.05）. The hysteromyomas of patients in group E＋H appeared as dominantly hyperechoic masses, and those of patients in group H appeared as hyperechoic tissue （non- mass）. The incidence of adverse reactions and pain score were higher in group H than those in group E ＋ H （P 〈 0.05）. Conclusion Ultrasound-guided inlra-hysteromyoma injection of ethyl alcohol absolute can enhance the energy deposition of HIFU in the uterine fibroids, improve the treatment efficiency, shorten the treatment time, reduce the treatment dose, and reduce the pain and complications for the patients.
基金The authors thank Brazilian Development BNDES for the economic support,the Joint Research Centre JRC for the technical assistance to this project and to Mr.Adam Aslam/Gabriel Santos for the grammar revision.
文摘A precise energy conversion factor is required to define the impact of greenhouse gas emissions by gasoline-powered vehi-cles and policies that will guide the application of future eco-innovations.The current energy conversion factor adopted by many countries is based on the Willans line approach,initially proposed in 1888 for steam engines,later adapted for internal combustion engines.The actual energy conversion factor,which defines the energy conversion for drivers in real traffic,is missing.In this article,eight world-class engines are tested in an engine bench for the acquisition of specific fuel consumption 3D maps.Then,their energy conversion factors,calculated by dividing the energy output by the energy input,are simulated in real and urban traffic,acquired according to the real driving emissions(RDE)cycle.In addition,a reference vehicle is instrumented to measure the energy input(fuel flow)and the energy output(mechanical energy in the half axles)under the same RDE cycle standards.The results of both procedures are very similar,respectively,0.405±0.04 L/kWh for the simulation based on eight benchmark engines,and 0.392±0.04 L/kWh for the reference vehicle driven in RDE traffic conditions,with a 95%confidence interval.For turbocharged engines,the factor attained by the simulation is 0.395±0.04 L/kWh.The values of the energy conversion factor for gasoline engines got in this research are higher than those obtained through the Willans line approach,suggesting a new standard value of 0.405 L/kWh,replacing the current 0.264 L/kWh.It could substantially change the greenhouse gas emissions in a tank-to-wheel approach for the entire vehicle and add-on eco-innovations.
基金Project supported by the National Natural Science Foundation of China(No.10572110)the Doctorate Foundation of the Chinese Education Ministrythe Doctorate Foundation of Xi'an Jiaotong University.
文摘By modeling metal as a special piezoelectric material with extremely small piezoelectricity and extremely large permittivity,we have obtained the analytical solutions for an interracial permeable crack in metal/piezoelectric bimaterials by means of the generalized Stroh formalism.The analysis shows that the stress fields near a permeable interracial crack tip are usually with three types of singularities:r^-1/2±iεand r^-1/2.Further numerical calculation on the oscillatory indexεare given for 28 types of metal/piezoelectric bimaterials combined by seven commercial piezoelectric materials:PZT-4,BaTiO3,PZT-5H,PZT-6B,PZT-7A,P-7 and PZT-PIC 151 and four metals:copper,silver,lead and aluminum,respectively.The explicit expressions of the crack tip energy release rate(ERR)and the crack tip generalized stress intensity factors(GSIF)are obtained.It is found that both the ERR and GSIF are independent of the electric displacement loading,although they seriously depends on the mechanical loadings.
基金the Fundamental Research Funds for the Central Universities in Donghua University and Shanghai Soft Science Research Project(No.23692120100).
文摘This study employed a difference-in-differences design to assess the effect of marketbased environmental regulation on green total factor energy efficiency(GTFEE)in a quasi-natural experiment that investigated China's carbon emissions trading scheme(ETS).The empirical results show that ETS had a positive effect on GTFEE.A series of robustness tests revealed that the results were robust.Potential mechanisms through which ETS can improve GTFEE include the promotion of technological innovation and the upgrading of industrial structure.The positive effects varied in different cities and diferent regions-the result was pronounced in eastern China and developed cities,but it was insignificant in central and western areas and developing cities.This study confirms the satisfactory performance of China's ETS in improving GTFEE,and this is relevant for other emerging countries.
基金supported by the National Natural Science Foundation of China(Grant No.51438002)
文摘In order to calculate the stress intensity factor(SIF) of crack tips in two-dimensional cracks from the viewpoint of strain energy density, a procedure to use the strain energy density factor to calculate the SIF is proposed. In this paper, the procedure is presented to calculate the SIF of crack tips in mode I cracks, mode II cracks and I+II mixed mode cracks. Meanwhile, the results are compared to those calculated by traditional approaches or other approaches based on strain energy density and verified by theoretical solutions. Furthermore, the effect of mesh density near the crack tip is discussed, and the proper location where the strain energy density factor is calculated is also studied. The results show that the SIF calculated by this procedure is close to not only those calculated by other approaches but also the theoretical solutions, thus it is capable of achieving accurate results.Besides, the mesh density around the crack tip should meet such requirements that, in the circular area created, the first layer of singular elements should have a radius about 0.05 mm and each element has a circumferential directional meshing angle to be15°–20°. Furthermore, for a single element around the crack tip, the strain energy density factor is suggested to be calculated in the location where half of the sector element's radius from the crack tip.
基金Project supported by the National Natural Science Foundation of China(Grant No.61371052).
文摘The size reduction of atomic clocks is a long-standing research issue.Many atomic clocks such as passive hydrogen masers(PHMs)and compact rubidium masers(CRMs)use iris-loaded resonance cavities(IRCs)as their microwave cavities because they can dramatically reduce the radical sizes of the atomic clocks.In this paper,the electromagnetic characteristic of the IRC is investigated by a theoretical model based on electromagnetic field theory.The formulas to calculate the resonance frequency,quality factor,and magnetic energy filling factor are presented.The relationship between the IRC structure and its electromagnetic characteristic is clarified.The theoretical calculation results accord well with the electromagnetic software simulations and experimental results.The results in this paper should be helpful in understanding the physical mechanism of the IRC and designing the atomic clocks.
文摘The torsional impact response of a penny-shaped crack in a nonhomogeneous strip is considered. The shear modulus is assumed to be functionally graded such that the mathematics is tractable. Laplace and Hankel transforms were used to reduce the problem to solving a Fredholm integral equation. The crack tip stress field is obtained by considering the asymptotic behavior of Bessel function. Explicit expressions of both the dynamic stress intensity factor and the energy density factor were derived.And it is shown that, as crack driving force, they are equivalent for the present crack problem. Investigated are the effects of material nonhomogeneity and (strip's) highness on the dynamic fracture behavior. Numerical results reveal that the peak of the dynamic stress intensity factor can be suppressed by increasing the nonhomogeneity parameter of the shear modulus, and that the dynamic behavior varies little with the adjusting of the strip's highness.
基金supported by the National Basic Research Program of China (973 Program) (No. 2007CB714605)
文摘With the background of offshore wind energy projects, this paper studies aerodynamic performance and geometric characteristics of large capacity wind turbine rotors （1 to 10 MW）, and the main characteristic parameters such as the rated wind speed, blade tip speed, and rotor solidity. We show that the essential criterion of a high- performance wind turbine is a highest possible annual usable energy pattern factor and a smallest possible dimension, capturing the maximum wind energy and producing the maximum annual power. The influence of the above-mentioned three parameters on the pattern factor and rotor geometry of wind turbine operated in China＇s offshore meteoro- logical environment is investigated. The variation patterns of aerodynamic and geometric parameters are obtained, analyzed, and compared with each other. The present method for aerodynamic analysis and its results can form a basis for evaluating aerodynamic performance of large-scale offshore wind turbine rotors.
