Phytophthora nicotianae causes substantial economic losses in most countries where tobacco is produced.At present,the control of P.nicotianae mainly depends on chemical methods,with considerable environmental and heal...Phytophthora nicotianae causes substantial economic losses in most countries where tobacco is produced.At present,the control of P.nicotianae mainly depends on chemical methods,with considerable environmental and health issues.We investigated the effects of ethanol extracts from Scutellaria baicalensis Georgi(SBG)and Magnolia officinalis(MO).On mycelial growth,sporangium formation,and zoospore release of P.nicotianae.Both extracts inhibited the growth of P.nicotianae,with mycelial growth inhibition rates of 88.92%and 93.92%,respectively,at 40 mg/mL,and EC50 values of 5.39 and 5.74 mg/mL,respectively.The underlying mechanisms were the inhibition of sporangium formation,the reduction of zoospore number,and the destruction of the mycelium structure.At an SBG extract concentration of 16.17 mg/mL,the inhibition rates for sporangia and zoospores were 98.66%and 99.39%,respectively.At an MO extract concentration of 2.87 mg/mL,the production of sporangia and zoospores was completely inhibited.The hyphae treated with the two plant extracts showed different degrees of deformation and damage.Hyphae treated with SBG extract showed adhesion and local swelling,whereas treatment with MO extract resulted in broken hyphae.Mixture of the extracts resulted in a good synergistic effect.展开更多
Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massi...Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.展开更多
Chinese fir(Cunninghamia lanceolata) is an excellent fast-growing timber species occurring in southern China and has significant value in the forestry industry. In order to enhance the phosphorus utilization efficienc...Chinese fir(Cunninghamia lanceolata) is an excellent fast-growing timber species occurring in southern China and has significant value in the forestry industry. In order to enhance the phosphorus utilization efficiency in Chinese fir, four clones named X6, S3, S39 and FK were used, and low phosphorus(LP) stress experiments were performed to analyze the response of different clones to phosphorus deficiency. According to the results on seedling height, maximum root length, leaf blade aspect ratio, root ratio, malondialdehyde content, acid phosphates activity,proline content, soluble protein level, and chlorophyll a and b levels of the tested clones, compared to the control groups(CK), the phosphorus high efficiency clone X6 was screen out for transcriptome sequencing experiments. De novo RNA-seq was then used to sequence the root transcriptomes of X6 under LP stress and CK, and we then compared the gene expression differences under the two conditions. A total of 3416 SDEGs were obtained by comparing the LP and CK groups, among which 1742 were up-regulated and 1682 were down-regulated. All SDEGs obtained from the LP and CK treated samples were subjected to KEGG annotation and classification. Through classification statistical analysis using WEGO software,607 SDEGs obtained KEGG pathway annotations, which were related to 206 metabolic pathways. In Chinese fir subjected to LP stress, 53 SDEGs related with phosphorus metabolism, and phosphate uptake and transport were obtained from our transcriptome data. Based on the phosphorus metabolism pathway obtained by KEGG classification, combined with previously report on gene annotation related with phosphorus metabolism, the enzymes encoded by SDEG related with phosphorus metabolism and their expression pattern were mapped onto phosphorus metabolism pathway.展开更多
The S-CO_(2) top-bottom combined cycle based on overlap energy utilization can lead to excessive heating area,due to the small temperature difference and the large thermal load for the heating surface at the tail of t...The S-CO_(2) top-bottom combined cycle based on overlap energy utilization can lead to excessive heating area,due to the small temperature difference and the large thermal load for the heating surface at the tail of the boiler.Therefore,reasonable optimization indexes are needed for design optimization.Common optimization indexes include heating area and working medium pressure drop,but lower working medium pressure drop usually leads to large heating area,for example,with the increase of tube inner diameter or boiler width,the pressure drop decreases but the heating area increases.Thus,if both are used as optimization indexes,it will be difficult to choose the optimum tube inner diameter and boiler width.In this paper,exergy loss analysis is used,in combination with economic analysis,the optimization index is unified to the cost per unit heat transfer of the heating surface.The thermal calculation and pressure drop calculation models are established for the heating surface at the tail of the boiler.The optimized heating surface can greatly improve the economic benefit.展开更多
Supercritical carbon dioxide(SCO_(2))power cycles,which uses CO_(2) as the working medium to realize thermal power conversion and output electric energy,was first proposed in the 1950s,but has not attracted widespread...Supercritical carbon dioxide(SCO_(2))power cycles,which uses CO_(2) as the working medium to realize thermal power conversion and output electric energy,was first proposed in the 1950s,but has not attracted widespread attention.At the beginning of this century,with the urgent need to reduce greenhouse gas emission and slow down the global warming trend,SCO_(2) power generation started to attract extensive interest.Compared to traditional water steam Rankine cycles,the SCO_(2) Brayton cycles have higher efficiency,more compact system to allow quick response to load variations,and better safety.展开更多
The design, construction and test of an Organic Rankine Cycle(ORC) with R123 as the working fluid were performed. A scroll expander was integrated in the system.The conductive oil with its temperature of 150 °C w...The design, construction and test of an Organic Rankine Cycle(ORC) with R123 as the working fluid were performed. A scroll expander was integrated in the system.The conductive oil with its temperature of 150 °C was used to simulate the low-grade heat source. An AC dynamometer unit measured the expander shaft torque, rotating speed and shaft power. The experiments were conducted in two operating modes: the constant mass flow rate and the constant shaft torque. Under the constant mass flow rate operating mode, the stepped increase of the shaft torque increased the expansion ratios of the expander and decreased the vapor superheats at the expander inlet. Thus,the shaft power and thermal efficiency were increased.Alternatively, the constant shaft torque operating mode involved two different regions, interfaced at the pumping frequency of 9 Hz. By the increase of the mass flow rates,the vapor superheats at the expander inlet was decreased and the shaft power was increased, but the ORC thermal efficiencies were slightly decreased. Both operating modes yielded the saturation shaft powers that were the maximum values one could use. It was found that the measured shaft powers and ORC thermal efficiencies were lower than the enthalpy determined values based on the fluid pressures and temperatures at the expander inlet and outlet. The maximum measured shaft power and thermal efficiency were 2.63 kW and 5.31 %, compared with the enthalpy determined values of 3.87 kW and 9.46 %, respectively.展开更多
Recently,our research group proposed the phase separation condenser tube,in which a mesh cylinder was inserted to form the flow structure of‘‘gas near the tube wall and liquid in the tube core’’,significantly enha...Recently,our research group proposed the phase separation condenser tube,in which a mesh cylinder was inserted to form the flow structure of‘‘gas near the tube wall and liquid in the tube core’’,significantly enhance the condensation heat transfer.But the bubble leakage towards the core region may worsen the heat transfer enhancement.In order to prevent the bubble leakage,the critical criterion was proposed based on the Young–Laplace equation,considering the inertia force,viscous force and pulsating flow.It was found that the critical criterion depends on the dimensionless parameter G*,the We number and a coefficient C.The numerical model was developed in terms of the volume of fluid method to predict the two-phase laminar flow in the phase separation condenser tube.The results show that the bubble leakage takes place at the bubble tip,which is agreed with the experimental observations.The critical curve distinguishing the non-bubble-breaking and bubble-breaking was obtained by comparing the bubble dynamics at different G*and We.The coefficient C was determined.The critical criterion for the bubble leakage is given as G We0:22We0:99349 G4:7 103 We0:00651t196:39We0:006514cosa DHW,providing the design and operation guidance for the phase separation condenser tube.展开更多
Renewable energy or low grade energy utilizations need high performance of phase change heat exchangers. Suspending micromembrane cylinder in tube(called modulated heat transfer tube) increases the void fractions or v...Renewable energy or low grade energy utilizations need high performance of phase change heat exchangers. Suspending micromembrane cylinder in tube(called modulated heat transfer tube) increases the void fractions or vapor qualities near the tube wall to significantly enhance heat transfer. The R123 condensation heat transfer with horizontal position was investigated. The results for the bare tube and modulated heat transfer tube were tested case by case. It is found that the modulated heat transfer tube significantly enhance the condensation heat transfer, with the heat transfer enhancement factors(EF)covering the range of 1.118–2.124. The comprehensive performance evaluation criteria(PEC) had the range of0.71–1.66, with most of runs behaving PEC larger than 1.0.For the two-phase outlet conditions, the EF values are increased with increases in the vapor mass fluxes, Gxin,where G is the mass flux and xinis the inlet vapor mass quality. The EF values are inversely related to Gxinfor the subcooled liquid outlet cases. The enhanced heat transfer mechanisms are analyzed with the observed images together with the discussion of pressure and velocity distributions.展开更多
Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption whil...Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption while complying with the SLA by maximizing physical machine(PM)-level utilization and load balancing techniques in infrastructure as a service.However,with the recent introduction of container as a service by cloud providers,containers are increasingly popular and will become the major deployment model in the cloud environment and specifically in platform as a service.Therefore,reducing power consumption while complying with the SLA at virtual machine(VM)-level becomes essential.In this context,we exploit a container consolidation scheme with usage prediction to achieve the above objectives.To obtain a reliable characterization of overutilized and underutilized PMs,our scheme jointly exploits the current and predicted CPU utilization based on local history of the considered PMs in the process of the container consolidation.We demonstrate our solution through simulations on real workloads.The experimental results show that the container consolidation scheme with usage prediction reduces the power consumption,number of container migrations,and average number of active VMs while complying with the SLA.展开更多
This Special Issue of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from the ICSCPS 2018,held in Beijing,China during June 29^th to July 1^st,2018.The conference was chaired by professor ...This Special Issue of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from the ICSCPS 2018,held in Beijing,China during June 29^th to July 1^st,2018.The conference was chaired by professor Jinliang Xu from the North China Electric Power University and sponsored by the Ministry of Science and Technology of China based on the National Key Research&Development Project“Fundamental studies and key technology development of high-efficiency carbon dioxide coal-fired power system”.展开更多
In this paper, an approach to optimize set points is proposed for controlled Organic Rankine Cycle(ORC)systems. Owing to both disturbances and variations of operating point existing in ORC systems, it is necessary to ...In this paper, an approach to optimize set points is proposed for controlled Organic Rankine Cycle(ORC)systems. Owing to both disturbances and variations of operating point existing in ORC systems, it is necessary to optimize the set points for controlled ORC systems so as to improve the energy conversion efficiency. At first, the optimal set points of controlled ORC systems are investigated by revisiting performance analysis and optimization of ORC systems. The expected set points of the evaporating pressure and the temperature at evaporator outlet are then determined by combining genetic algorithm with least squares support vector machine(GA-LSSVM). Simulation results show that the predicted results by GA-LSSVM can be regarded as the optimal set points of controlled ORC systems with varying operating conditions.展开更多
In this study,GaN-based light-emitting diodes(LEDs)with and without AlGaInN electron blocking layer(EBL)under self-heating effect are numerically studied.The energy band diagram,carrier transport and distribution char...In this study,GaN-based light-emitting diodes(LEDs)with and without AlGaInN electron blocking layer(EBL)under self-heating effect are numerically studied.The energy band diagram,carrier transport and distribution characteristics,internal Joule heat and non-radiative recombination heat characteristics,and internal quantum efficiency are investigated.The effect of Auger recombination coefficient on efficiency droop under self-heating effect is also studied.The simulation results show that efficiency droop is markedly improved when an AlGaInN EBL is placed between p-type GaN layer and active region.However,the chip temperature of LED is significantly increased simultaneously.The results also indicate that Auger recombination can be neglected because it is not the major contributor for the internal heat source.The efficiency droop is unrelated to the internal heat source.However,both electron leakage and Auger recombination play important roles in efficiency droop mechanism under self-heating effect.展开更多
基金funded by financial grants from the Education Department of Hunan Province(SCX1840 and CX20190515).
文摘Phytophthora nicotianae causes substantial economic losses in most countries where tobacco is produced.At present,the control of P.nicotianae mainly depends on chemical methods,with considerable environmental and health issues.We investigated the effects of ethanol extracts from Scutellaria baicalensis Georgi(SBG)and Magnolia officinalis(MO).On mycelial growth,sporangium formation,and zoospore release of P.nicotianae.Both extracts inhibited the growth of P.nicotianae,with mycelial growth inhibition rates of 88.92%and 93.92%,respectively,at 40 mg/mL,and EC50 values of 5.39 and 5.74 mg/mL,respectively.The underlying mechanisms were the inhibition of sporangium formation,the reduction of zoospore number,and the destruction of the mycelium structure.At an SBG extract concentration of 16.17 mg/mL,the inhibition rates for sporangia and zoospores were 98.66%and 99.39%,respectively.At an MO extract concentration of 2.87 mg/mL,the production of sporangia and zoospores was completely inhibited.The hyphae treated with the two plant extracts showed different degrees of deformation and damage.Hyphae treated with SBG extract showed adhesion and local swelling,whereas treatment with MO extract resulted in broken hyphae.Mixture of the extracts resulted in a good synergistic effect.
基金supported in part by the National Science Foundation of China(Grant No.61922017).
文摘Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.
基金supported by the State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University)support Program(Grant No.201201)
文摘Chinese fir(Cunninghamia lanceolata) is an excellent fast-growing timber species occurring in southern China and has significant value in the forestry industry. In order to enhance the phosphorus utilization efficiency in Chinese fir, four clones named X6, S3, S39 and FK were used, and low phosphorus(LP) stress experiments were performed to analyze the response of different clones to phosphorus deficiency. According to the results on seedling height, maximum root length, leaf blade aspect ratio, root ratio, malondialdehyde content, acid phosphates activity,proline content, soluble protein level, and chlorophyll a and b levels of the tested clones, compared to the control groups(CK), the phosphorus high efficiency clone X6 was screen out for transcriptome sequencing experiments. De novo RNA-seq was then used to sequence the root transcriptomes of X6 under LP stress and CK, and we then compared the gene expression differences under the two conditions. A total of 3416 SDEGs were obtained by comparing the LP and CK groups, among which 1742 were up-regulated and 1682 were down-regulated. All SDEGs obtained from the LP and CK treated samples were subjected to KEGG annotation and classification. Through classification statistical analysis using WEGO software,607 SDEGs obtained KEGG pathway annotations, which were related to 206 metabolic pathways. In Chinese fir subjected to LP stress, 53 SDEGs related with phosphorus metabolism, and phosphate uptake and transport were obtained from our transcriptome data. Based on the phosphorus metabolism pathway obtained by KEGG classification, combined with previously report on gene annotation related with phosphorus metabolism, the enzymes encoded by SDEG related with phosphorus metabolism and their expression pattern were mapped onto phosphorus metabolism pathway.
基金This work is supported by Beijing Nova Program(Z211100002121158).The authors are most grateful to Ms.Chao Liu at the North China Electric Power University for her help and advice during the preparation of this paper.
文摘The S-CO_(2) top-bottom combined cycle based on overlap energy utilization can lead to excessive heating area,due to the small temperature difference and the large thermal load for the heating surface at the tail of the boiler.Therefore,reasonable optimization indexes are needed for design optimization.Common optimization indexes include heating area and working medium pressure drop,but lower working medium pressure drop usually leads to large heating area,for example,with the increase of tube inner diameter or boiler width,the pressure drop decreases but the heating area increases.Thus,if both are used as optimization indexes,it will be difficult to choose the optimum tube inner diameter and boiler width.In this paper,exergy loss analysis is used,in combination with economic analysis,the optimization index is unified to the cost per unit heat transfer of the heating surface.The thermal calculation and pressure drop calculation models are established for the heating surface at the tail of the boiler.The optimized heating surface can greatly improve the economic benefit.
文摘Supercritical carbon dioxide(SCO_(2))power cycles,which uses CO_(2) as the working medium to realize thermal power conversion and output electric energy,was first proposed in the 1950s,but has not attracted widespread attention.At the beginning of this century,with the urgent need to reduce greenhouse gas emission and slow down the global warming trend,SCO_(2) power generation started to attract extensive interest.Compared to traditional water steam Rankine cycles,the SCO_(2) Brayton cycles have higher efficiency,more compact system to allow quick response to load variations,and better safety.
基金supported by the National Basic Research Program of China(2011CB710703)the National Natural Science Foundation of China(51306048,51210011)
文摘The design, construction and test of an Organic Rankine Cycle(ORC) with R123 as the working fluid were performed. A scroll expander was integrated in the system.The conductive oil with its temperature of 150 °C was used to simulate the low-grade heat source. An AC dynamometer unit measured the expander shaft torque, rotating speed and shaft power. The experiments were conducted in two operating modes: the constant mass flow rate and the constant shaft torque. Under the constant mass flow rate operating mode, the stepped increase of the shaft torque increased the expansion ratios of the expander and decreased the vapor superheats at the expander inlet. Thus,the shaft power and thermal efficiency were increased.Alternatively, the constant shaft torque operating mode involved two different regions, interfaced at the pumping frequency of 9 Hz. By the increase of the mass flow rates,the vapor superheats at the expander inlet was decreased and the shaft power was increased, but the ORC thermal efficiencies were slightly decreased. Both operating modes yielded the saturation shaft powers that were the maximum values one could use. It was found that the measured shaft powers and ORC thermal efficiencies were lower than the enthalpy determined values based on the fluid pressures and temperatures at the expander inlet and outlet. The maximum measured shaft power and thermal efficiency were 2.63 kW and 5.31 %, compared with the enthalpy determined values of 3.87 kW and 9.46 %, respectively.
基金supported by the National Natural Science Foundation of China of International Cooperation Project (51210011)the National Basic Research Program of China (2011CB710703)+1 种基金the Young Scientists Fund of the National Natural Science Foundation of China (51106049)the Fundamental Research Funds for the Central Universities (JB2013144)
文摘Recently,our research group proposed the phase separation condenser tube,in which a mesh cylinder was inserted to form the flow structure of‘‘gas near the tube wall and liquid in the tube core’’,significantly enhance the condensation heat transfer.But the bubble leakage towards the core region may worsen the heat transfer enhancement.In order to prevent the bubble leakage,the critical criterion was proposed based on the Young–Laplace equation,considering the inertia force,viscous force and pulsating flow.It was found that the critical criterion depends on the dimensionless parameter G*,the We number and a coefficient C.The numerical model was developed in terms of the volume of fluid method to predict the two-phase laminar flow in the phase separation condenser tube.The results show that the bubble leakage takes place at the bubble tip,which is agreed with the experimental observations.The critical curve distinguishing the non-bubble-breaking and bubble-breaking was obtained by comparing the bubble dynamics at different G*and We.The coefficient C was determined.The critical criterion for the bubble leakage is given as G We0:22We0:99349 G4:7 103 We0:00651t196:39We0:006514cosa DHW,providing the design and operation guidance for the phase separation condenser tube.
基金supported by the National Natural Science Foundation of China of International Cooperation Project (51210011)the National Basic Research Program of China (2011CB710703)the National Natural Science Foundation of China (U1034004)
文摘Renewable energy or low grade energy utilizations need high performance of phase change heat exchangers. Suspending micromembrane cylinder in tube(called modulated heat transfer tube) increases the void fractions or vapor qualities near the tube wall to significantly enhance heat transfer. The R123 condensation heat transfer with horizontal position was investigated. The results for the bare tube and modulated heat transfer tube were tested case by case. It is found that the modulated heat transfer tube significantly enhance the condensation heat transfer, with the heat transfer enhancement factors(EF)covering the range of 1.118–2.124. The comprehensive performance evaluation criteria(PEC) had the range of0.71–1.66, with most of runs behaving PEC larger than 1.0.For the two-phase outlet conditions, the EF values are increased with increases in the vapor mass fluxes, Gxin,where G is the mass flux and xinis the inlet vapor mass quality. The EF values are inversely related to Gxinfor the subcooled liquid outlet cases. The enhanced heat transfer mechanisms are analyzed with the observed images together with the discussion of pressure and velocity distributions.
基金The work presented in this paper was supported by the NSFC(Grant Nos.61472047 and 61602054)Beijing Natural Science Foundation(4174100).
文摘Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption while complying with the SLA by maximizing physical machine(PM)-level utilization and load balancing techniques in infrastructure as a service.However,with the recent introduction of container as a service by cloud providers,containers are increasingly popular and will become the major deployment model in the cloud environment and specifically in platform as a service.Therefore,reducing power consumption while complying with the SLA at virtual machine(VM)-level becomes essential.In this context,we exploit a container consolidation scheme with usage prediction to achieve the above objectives.To obtain a reliable characterization of overutilized and underutilized PMs,our scheme jointly exploits the current and predicted CPU utilization based on local history of the considered PMs in the process of the container consolidation.We demonstrate our solution through simulations on real workloads.The experimental results show that the container consolidation scheme with usage prediction reduces the power consumption,number of container migrations,and average number of active VMs while complying with the SLA.
文摘This Special Issue of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from the ICSCPS 2018,held in Beijing,China during June 29^th to July 1^st,2018.The conference was chaired by professor Jinliang Xu from the North China Electric Power University and sponsored by the Ministry of Science and Technology of China based on the National Key Research&Development Project“Fundamental studies and key technology development of high-efficiency carbon dioxide coal-fired power system”.
基金supported by the National Basic Research Program of China(2011CB710706)the National Natural Science Foundation of China(51210011,61374025)
文摘In this paper, an approach to optimize set points is proposed for controlled Organic Rankine Cycle(ORC)systems. Owing to both disturbances and variations of operating point existing in ORC systems, it is necessary to optimize the set points for controlled ORC systems so as to improve the energy conversion efficiency. At first, the optimal set points of controlled ORC systems are investigated by revisiting performance analysis and optimization of ORC systems. The expected set points of the evaporating pressure and the temperature at evaporator outlet are then determined by combining genetic algorithm with least squares support vector machine(GA-LSSVM). Simulation results show that the predicted results by GA-LSSVM can be regarded as the optimal set points of controlled ORC systems with varying operating conditions.
基金supported by the National Natural Science Foundation of China (U1034004, 51210011, 50825603)the Fundamental Research Funds for the Central Universities, China (12QX14)
文摘In this study,GaN-based light-emitting diodes(LEDs)with and without AlGaInN electron blocking layer(EBL)under self-heating effect are numerically studied.The energy band diagram,carrier transport and distribution characteristics,internal Joule heat and non-radiative recombination heat characteristics,and internal quantum efficiency are investigated.The effect of Auger recombination coefficient on efficiency droop under self-heating effect is also studied.The simulation results show that efficiency droop is markedly improved when an AlGaInN EBL is placed between p-type GaN layer and active region.However,the chip temperature of LED is significantly increased simultaneously.The results also indicate that Auger recombination can be neglected because it is not the major contributor for the internal heat source.The efficiency droop is unrelated to the internal heat source.However,both electron leakage and Auger recombination play important roles in efficiency droop mechanism under self-heating effect.
