Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not be...Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered yet.Moreover,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy consumption.Optimizing three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making time.To tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and UAVs.Then,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put forward.We formally proved that a stable matching can be achieved by our proposal.Extensive simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.展开更多
Cloud-as-the-center computing paradigms face multiple challenges in the 5G and Internet of Things scenarios, where the service requests are usually initiated by the end-user devices located at network edge and have ri...Cloud-as-the-center computing paradigms face multiple challenges in the 5G and Internet of Things scenarios, where the service requests are usually initiated by the end-user devices located at network edge and have rigid time constraints. Therefore, Fog computing, or mobile edge computing, is introduced as a promising solution to the service provision in the tiered IoT infrastructure to compensate the shortage of traditional cloud-only architecture. In this cloud-to-things continuum, several cloudlet or mobile edge server entities are placed at the access network to handle the task offloading and processing problems at the network edge. This raises the resource scheduling problem in this tiered system, which is vital for the promotion of the system efficiency. Therefore, in this paper, a scheduling mechanism for the cloudlets or fog nodes are presented, which takes the mobile tasks’ deadline and resources requirements at the same time while promoting the overall profit of the system. First, the problem at the cloudlet, to which IoT devices offload their tasks, is formulated as a multi-dimensional 0-1 knapsack problem. Second, based on ant colony optimization, a scheduling algorithm is presented which treat this problem as a subset selection problem. Third, to promote the performance of the system in the dynamic environments,a churn-refined algorithm is further put forward. A series of simulation experiments have shown that out proposal outperforms many state-of-the-art algorithms in both profit and guarantee ratio.展开更多
[Objectives] To use co-clustering analysis and visualization method to analyze the research on Siraitiae Fructus in recent ten years,to know the hot spots and trend of research. [Methods] Relevant research results abo...[Objectives] To use co-clustering analysis and visualization method to analyze the research on Siraitiae Fructus in recent ten years,to know the hot spots and trend of research. [Methods] Relevant research results about S. Fructus in CNKI from January of 2007 to December of 2016 were retrieved by computers,and the retrieval time was February 20,2017. BICOMB,Net Draw,g CLUTO and SPSS19. 0 software were used to conduct co-clustering analysis and visualization analysis for included articles. Keywords were analyzed,and social network graph,visualization matrix,peak image and multidimensional scaling analysis map were drawn. Correlation among high-frequency key words were analyzed. [Results] Totally 723 articles were included,among which 70 articles were issued during 2012-2016; 76 key words were obtained by key word co-occurrence network map,among which mogroside,MOG,extraction process,tissue culture,cultivation technology,varieties,growth and development were in the core position; visualization and the peak image showed that the topics in this research field could be divided into 6 categories; research hotspot dynamic evolution showed that S. Fructus flower,beverage,total flavonoids,gene expression,gene cloning,enzyme,apoptosis,and S. Fructus seed oil would be the hot spots of further study. [Conclusions]This study reveals that the research on S. Fructus in the recent ten years is becoming mature,and expanding to deep level. This study can be promoted to discipline development evaluation of TCM research field.展开更多
Objective:To compare the feasibility and safety between right distal radial artery access and right radial artery access in patients undergoing coronary angiography(CAG)or percutaneous coronary intervention(PCI).Metho...Objective:To compare the feasibility and safety between right distal radial artery access and right radial artery access in patients undergoing coronary angiography(CAG)or percutaneous coronary intervention(PCI).Methods:On the basis of arterial access,113 patients who underwent CAG or PCI in Kunshan Hospital of Traditional Chinese Medicine between January and October 2018 were divided into two groups:a right distal radial artery group(52 patients)and a right radial artery group(61 patients).We collected general information,the number of puncture attempts,access times,postoperative compression time,and complications.Results:The general characteristics,rate of successful radial artery puncture,and rate of successful catheter placement in the two groups were not different.The right radial artery group had fewer puncture attempts(1.26±0.44 times vs.2.19±0.53 times,P=0.001)and a shorter access time(3.23±0.86 min vs.4.77±1.49 min,P=0.001)than the right distal radial artery group.However,the postoperative compression time in the right distal radial artery group was shorter(3.44±0.9 h vs.7.16±1.21 h,P=0.001).Two cases of bleeding,four cases of hematoma,and one case of artery occlusion in the right radial artery group and one case of hematoma in the right distal artery group occurred before discharge.The rate of total complications in the right distal radial artery group was lower than in the right radial artery group(1.93%vs.11.48%,P=0.048).Conclusion:CAG or PCI through the right distal radial artery is feasible and safe.展开更多
Through caching popular contents at the network edge,wireless edge caching can greatly reduce both the content request latency at mobile devices and the traffic burden at the core network.However,popularity-based cach...Through caching popular contents at the network edge,wireless edge caching can greatly reduce both the content request latency at mobile devices and the traffic burden at the core network.However,popularity-based caching strategies are vulnerable to Cache Pollution Attacks(CPAs)due to the weak security protection at both edge nodes and mobile devices.In CPAs,through initiating a large number of requests for unpopular contents,malicious users can pollute the edge caching space and degrade the caching efficiency.This paper firstly integrates the dynamic nature of content request and mobile devices into the edge caching framework,and introduces an eavesdroppingbased CPA strategy.Then,an edge caching mechanism,which contains a Request Pattern Change-based Cache Pollution Detection(RPC2PD)algorithm and an Attack-aware Cache Defense(ACD)algorithm,is proposed to defend against CPAs.Simulation results show that the proposed mechanism could effectively suppress the effects of CPAs on the caching performance and improve the cache hit ratio.展开更多
Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of suc...Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of successful ablation of PVCs from the proximal LBB within the right coronary cusp(RCC).Case presentation:Our patient was a 70-year-old woman with PVCs from the proximal LBB that were successfully ablated via the RCC through radiofrequency catheter ablation with a 3D mapping system;she had a complication of incomplete right bundle branch block(RBBB)and remained asymptomatic during follow-up.Conclusion:The RCC provides an alternative approach for ablating PVCs originating from the proximal LBB,ow-ing to the close relationship between the RCC and proximal LBB.展开更多
Kunming Basin locates middle of Yunnan altiplano and has a particularity in geography,topographic and geological environment.With the urban dilation quickly,add the reason of the unreasonable city layout,conflicts bet...Kunming Basin locates middle of Yunnan altiplano and has a particularity in geography,topographic and geological environment.With the urban dilation quickly,add the reason of the unreasonable city layout,conflicts between environment and urban resources consumption become shrill increasingly.It is human being activities that lead to vulnerability and depravation of geological environment in local.Take a few examples on geological environment to expatiate relationship between urban construction and geological environment carrying capacity,and find a way how to make a better plan for urban sustainable development to achieve new balance between man and nature in local.展开更多
Silver nanoparticles(AgNPs)are widely used in antimicrobial applications.However,its easy aggregation and rapid loss hinder the effective antifouling.To address this issue,a novel stimuli-responsive antibacterial nano...Silver nanoparticles(AgNPs)are widely used in antimicrobial applications.However,its easy aggregation and rapid loss hinder the effective antifouling.To address this issue,a novel stimuli-responsive antibacterial nanocomposite(Ag@SP-MSN)was developed based on spiropyran covalently conjugated mesoporous silica nanoparticles(284.6 nm)and AgNPs(27.1 nm)via strong electrostatic attraction.Both transmission electron microscopy(TEM)and atomic force microscopy(AFM)images proved the successful modification of AgNPs onto SP-MSN.The light-induced maximum loading amount towards AgNPs was calculated to be 95.0 wt.%after ultraviolet irradiation,while the amount of AgNPs released from Ag@SP-MSN was 94.4 wt.%under visible light in the aid of ammonia(0.1%,v/v).Upon cycled light irradiation,Ag@SP-MSN could recover 84.5 wt.%of AgNPs even after four cycles.The proposed Ag@SP-MSN exhibited better antibacterial activity against both E.coli and S.aureus than Ag@MSN under visible light illumination,indicating the efficient photo-responsive isomerization of spiropyran.Furthermore,the Ag@SP-MSN embedded gel demonstrated outstanding antifouling ability even after 21 days when compared to AgNPs gel.The long-term photo-controllable antifouling property proved the excellent reversible absorption and release of Ag@SP-MSN towards AgNPs.This work provides new insights into the safe utilization of nanomaterials,offering promising advancements to meet clinical antibacterial requirements.展开更多
The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water p...The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water pit was developed based on the coordinate transformation method and validated by experimental results from the water pit heat storage in Huangdicheng in 2018.The thermal performance of 26 water pits with different heights and side wall slopes was calculated for 10 consecutive years.It takes four to six years for the water pit to reach steady-state operation.The operation data from the tenth year was selected to evaluate the thermal performance of each configuration.The results show that because of the thermal insulation on top of the water pit,the height to diameter ratio of a water pit with minimum annual heat loss was always smaller than 1.0.The annual storage efficiency of a water pit increases with side wall slope due to the reduced side wall area.There is an almost linear increase in the thermal stratification number of a water pit with height.With an increase in the height,thermal stratification in water pits with a steeper slope increased more gradually than water pits with a lower slope.The findings in this paper are relevant for the design optimization of water pits as seasonal thermal energy storages.展开更多
To realize the goal of net zero energy building(NZEB),the integration of renewable energy and novel design of buildings is needed.The paths of energy demand reduction and additional energy supply with renewables are s...To realize the goal of net zero energy building(NZEB),the integration of renewable energy and novel design of buildings is needed.The paths of energy demand reduction and additional energy supply with renewables are separated.In this study,those two are merged into one integration.The concept is based on the combination of photovoltaic,thermoelectric modules,energy storage and control algorithms.Five types of building envelope systems,namely PV+TE(S1),Grid+TE(S2),PV+Grid+TE(S3),PV+Battery+TE(S4)and PV+Grid+Battery+TE(S5)are studied,from aspects of energy,economic and environmental(E3)performance.The new envelope systems can achieve thermal load reduction while providing additional cooling/heating supply,which can promote advance of NZEBs.It is found that there is a typical optimum setting of thermal energy load for each one of them with minimum annual power consumption.Except for the S1 system,the rest can realize negative accumulated power consumption in a year-round operation,which means the thermal load of building envelope could be zero.The uniform annual cost for S1 to S5 under interest rate of 0.04 are 19.78,14.77,23.83,60.53,64.94$/m2,respectively.The S5 system has the highest environmental effect with 3.04 t/m2 reduction of CO_(2) over 30 years of operation.展开更多
Cyanobacteria can utilize CO2 or even N2 to produce a variety of high value-added products efficiently.Plastoquinone(PQ)is an important electron carrier in both of the photosynthetic and respiratory electron transport...Cyanobacteria can utilize CO2 or even N2 to produce a variety of high value-added products efficiently.Plastoquinone(PQ)is an important electron carrier in both of the photosynthetic and respiratory electron transport chain.Although the content of PQ,as well as their redox state,have an important effect on physiology and metabolism,there are relatively few studies on the synthesis of PQ and its related metabolic regulation mechanism in photosynthetic microorganisms.In this study,the strategies of overexpression of Geranyl diphosphate:4-hydroxybenzoate geranyltransferase(lepgt)and addition of 4-hydroxybenzoate(4-HB)as the quinone ring precursor were adopted to regulate the biosynthesis of PQ in Synechocystis PCC 6803.Combined with the analysis the photosystem activity,respiration rate and metabolic components,we found the changes of intracellular PQ reprogrammed the metabolism of Synechocystis PCC 6803.The results showed that the overexpression of lepgt reduced PQ content dramatically,by 22.18%.Interestingly,both of the photosynthesis and respiration rate were enhanced.In addition,the intracellular lipid and protein contents were significantly increased.Whereas,the addition of low concentrations of 4-HB enhanced the biosynthesis of PQ,and the intracellular PQ contents were increased by 14.76%-70.86%in different conditions.Addition of 4-HB can regulate the photosystem efficiency and respiration and reprogram the metabolism of Synechocystis PCC 6803 efficiently.In a word,regulating the PQ biosynthesis provided a novel idea for promoting the reprogramming the physiology and metabolism of Synechocystis.展开更多
It is necessary to satisfy the flexible requirements of solar heat storage systems to provide efficient heating and constant-temperature domestic hot water at different periods.A novel heat storage tank with both stra...It is necessary to satisfy the flexible requirements of solar heat storage systems to provide efficient heating and constant-temperature domestic hot water at different periods.A novel heat storage tank with both stratified and mixing functions is proposed,which can realize the integration of stable stratification and rapid mixing modes.In this research,a three-dimensional heat transfer model of the heat storage tank with stratified and mixed dual modes was established,and a thermal performance test system for the tank was built in the State Key Laboratory of Green Building in Western China.Moreover,a new evaluation index representing the mixing speed is proposed.The stratification effect and mixing characteristics of the tank were studied under different comprehensive conditions.The results show that the exergy efficiency of the tank with a stratified pipe can be increased by 10%–15%compared to that of a conventional tank.Additionally,the recommended optimal flow rate range for well-stratified tanks is 4–6 L/min.The mixing nozzle of the tank reduces the mixing reaction coefficient by 0.27 and significantly reduces the mixing time.This study provides critical guidance to meet the flexible thermal needs of users and implement high-performance applications using the stratified and mixing modes of heat storage tanks.展开更多
基金supported by the National Natural Science Foundation of China under Grant 62171465。
文摘Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered yet.Moreover,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy consumption.Optimizing three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making time.To tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and UAVs.Then,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put forward.We formally proved that a stable matching can be achieved by our proposal.Extensive simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.
文摘Cloud-as-the-center computing paradigms face multiple challenges in the 5G and Internet of Things scenarios, where the service requests are usually initiated by the end-user devices located at network edge and have rigid time constraints. Therefore, Fog computing, or mobile edge computing, is introduced as a promising solution to the service provision in the tiered IoT infrastructure to compensate the shortage of traditional cloud-only architecture. In this cloud-to-things continuum, several cloudlet or mobile edge server entities are placed at the access network to handle the task offloading and processing problems at the network edge. This raises the resource scheduling problem in this tiered system, which is vital for the promotion of the system efficiency. Therefore, in this paper, a scheduling mechanism for the cloudlets or fog nodes are presented, which takes the mobile tasks’ deadline and resources requirements at the same time while promoting the overall profit of the system. First, the problem at the cloudlet, to which IoT devices offload their tasks, is formulated as a multi-dimensional 0-1 knapsack problem. Second, based on ant colony optimization, a scheduling algorithm is presented which treat this problem as a subset selection problem. Third, to promote the performance of the system in the dynamic environments,a churn-refined algorithm is further put forward. A series of simulation experiments have shown that out proposal outperforms many state-of-the-art algorithms in both profit and guarantee ratio.
基金Supported by Guangxi Major Scientific Research and Technological Development Project(Gui Ke Zhong 1355001-4,14124002-11)
文摘[Objectives] To use co-clustering analysis and visualization method to analyze the research on Siraitiae Fructus in recent ten years,to know the hot spots and trend of research. [Methods] Relevant research results about S. Fructus in CNKI from January of 2007 to December of 2016 were retrieved by computers,and the retrieval time was February 20,2017. BICOMB,Net Draw,g CLUTO and SPSS19. 0 software were used to conduct co-clustering analysis and visualization analysis for included articles. Keywords were analyzed,and social network graph,visualization matrix,peak image and multidimensional scaling analysis map were drawn. Correlation among high-frequency key words were analyzed. [Results] Totally 723 articles were included,among which 70 articles were issued during 2012-2016; 76 key words were obtained by key word co-occurrence network map,among which mogroside,MOG,extraction process,tissue culture,cultivation technology,varieties,growth and development were in the core position; visualization and the peak image showed that the topics in this research field could be divided into 6 categories; research hotspot dynamic evolution showed that S. Fructus flower,beverage,total flavonoids,gene expression,gene cloning,enzyme,apoptosis,and S. Fructus seed oil would be the hot spots of further study. [Conclusions]This study reveals that the research on S. Fructus in the recent ten years is becoming mature,and expanding to deep level. This study can be promoted to discipline development evaluation of TCM research field.
文摘Objective:To compare the feasibility and safety between right distal radial artery access and right radial artery access in patients undergoing coronary angiography(CAG)or percutaneous coronary intervention(PCI).Methods:On the basis of arterial access,113 patients who underwent CAG or PCI in Kunshan Hospital of Traditional Chinese Medicine between January and October 2018 were divided into two groups:a right distal radial artery group(52 patients)and a right radial artery group(61 patients).We collected general information,the number of puncture attempts,access times,postoperative compression time,and complications.Results:The general characteristics,rate of successful radial artery puncture,and rate of successful catheter placement in the two groups were not different.The right radial artery group had fewer puncture attempts(1.26±0.44 times vs.2.19±0.53 times,P=0.001)and a shorter access time(3.23±0.86 min vs.4.77±1.49 min,P=0.001)than the right distal radial artery group.However,the postoperative compression time in the right distal radial artery group was shorter(3.44±0.9 h vs.7.16±1.21 h,P=0.001).Two cases of bleeding,four cases of hematoma,and one case of artery occlusion in the right radial artery group and one case of hematoma in the right distal artery group occurred before discharge.The rate of total complications in the right distal radial artery group was lower than in the right radial artery group(1.93%vs.11.48%,P=0.048).Conclusion:CAG or PCI through the right distal radial artery is feasible and safe.
文摘Through caching popular contents at the network edge,wireless edge caching can greatly reduce both the content request latency at mobile devices and the traffic burden at the core network.However,popularity-based caching strategies are vulnerable to Cache Pollution Attacks(CPAs)due to the weak security protection at both edge nodes and mobile devices.In CPAs,through initiating a large number of requests for unpopular contents,malicious users can pollute the edge caching space and degrade the caching efficiency.This paper firstly integrates the dynamic nature of content request and mobile devices into the edge caching framework,and introduces an eavesdroppingbased CPA strategy.Then,an edge caching mechanism,which contains a Request Pattern Change-based Cache Pollution Detection(RPC2PD)algorithm and an Attack-aware Cache Defense(ACD)algorithm,is proposed to defend against CPAs.Simulation results show that the proposed mechanism could effectively suppress the effects of CPAs on the caching performance and improve the cache hit ratio.
文摘Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of successful ablation of PVCs from the proximal LBB within the right coronary cusp(RCC).Case presentation:Our patient was a 70-year-old woman with PVCs from the proximal LBB that were successfully ablated via the RCC through radiofrequency catheter ablation with a 3D mapping system;she had a complication of incomplete right bundle branch block(RBBB)and remained asymptomatic during follow-up.Conclusion:The RCC provides an alternative approach for ablating PVCs originating from the proximal LBB,ow-ing to the close relationship between the RCC and proximal LBB.
文摘Kunming Basin locates middle of Yunnan altiplano and has a particularity in geography,topographic and geological environment.With the urban dilation quickly,add the reason of the unreasonable city layout,conflicts between environment and urban resources consumption become shrill increasingly.It is human being activities that lead to vulnerability and depravation of geological environment in local.Take a few examples on geological environment to expatiate relationship between urban construction and geological environment carrying capacity,and find a way how to make a better plan for urban sustainable development to achieve new balance between man and nature in local.
基金supported by the National Natural Science Foundation of China(No.21804043)the Funding Project of the State Key Laboratory of Bioreactor Engineering.
文摘Silver nanoparticles(AgNPs)are widely used in antimicrobial applications.However,its easy aggregation and rapid loss hinder the effective antifouling.To address this issue,a novel stimuli-responsive antibacterial nanocomposite(Ag@SP-MSN)was developed based on spiropyran covalently conjugated mesoporous silica nanoparticles(284.6 nm)and AgNPs(27.1 nm)via strong electrostatic attraction.Both transmission electron microscopy(TEM)and atomic force microscopy(AFM)images proved the successful modification of AgNPs onto SP-MSN.The light-induced maximum loading amount towards AgNPs was calculated to be 95.0 wt.%after ultraviolet irradiation,while the amount of AgNPs released from Ag@SP-MSN was 94.4 wt.%under visible light in the aid of ammonia(0.1%,v/v).Upon cycled light irradiation,Ag@SP-MSN could recover 84.5 wt.%of AgNPs even after four cycles.The proposed Ag@SP-MSN exhibited better antibacterial activity against both E.coli and S.aureus than Ag@MSN under visible light illumination,indicating the efficient photo-responsive isomerization of spiropyran.Furthermore,the Ag@SP-MSN embedded gel demonstrated outstanding antifouling ability even after 21 days when compared to AgNPs gel.The long-term photo-controllable antifouling property proved the excellent reversible absorption and release of Ag@SP-MSN towards AgNPs.This work provides new insights into the safe utilization of nanomaterials,offering promising advancements to meet clinical antibacterial requirements.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21050200)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2013N070)the State Grid Corporation Science and Technology Project“Research on Comprehensive Development and Utilization Technology of Renewable Energy in Multi-format Ecological Development Zone”for funding this project.
文摘The aim of the study is to investigate the influence of geometry on the thermal capacity and stratifications of a water pit heat storage for solar district heating.A TRNSYS component model for a truncated cone water pit was developed based on the coordinate transformation method and validated by experimental results from the water pit heat storage in Huangdicheng in 2018.The thermal performance of 26 water pits with different heights and side wall slopes was calculated for 10 consecutive years.It takes four to six years for the water pit to reach steady-state operation.The operation data from the tenth year was selected to evaluate the thermal performance of each configuration.The results show that because of the thermal insulation on top of the water pit,the height to diameter ratio of a water pit with minimum annual heat loss was always smaller than 1.0.The annual storage efficiency of a water pit increases with side wall slope due to the reduced side wall area.There is an almost linear increase in the thermal stratification number of a water pit with height.With an increase in the height,thermal stratification in water pits with a steeper slope increased more gradually than water pits with a lower slope.The findings in this paper are relevant for the design optimization of water pits as seasonal thermal energy storages.
基金supported by the National Key R&D Program of China(No.2019YFE0193100,No.2021YFE0113500)the Fundamental Research Funds for the Central Universities,China(No.2019kfyXJJS189,No.2020kfyXJJS097)Research Project of the Ministry of Housing and Urban-Rural Development of China“Research and Demonstration of Optimal Configuration of Energy Storage System in Nearly Zero Energy Communities”(K20210466).
文摘To realize the goal of net zero energy building(NZEB),the integration of renewable energy and novel design of buildings is needed.The paths of energy demand reduction and additional energy supply with renewables are separated.In this study,those two are merged into one integration.The concept is based on the combination of photovoltaic,thermoelectric modules,energy storage and control algorithms.Five types of building envelope systems,namely PV+TE(S1),Grid+TE(S2),PV+Grid+TE(S3),PV+Battery+TE(S4)and PV+Grid+Battery+TE(S5)are studied,from aspects of energy,economic and environmental(E3)performance.The new envelope systems can achieve thermal load reduction while providing additional cooling/heating supply,which can promote advance of NZEBs.It is found that there is a typical optimum setting of thermal energy load for each one of them with minimum annual power consumption.Except for the S1 system,the rest can realize negative accumulated power consumption in a year-round operation,which means the thermal load of building envelope could be zero.The uniform annual cost for S1 to S5 under interest rate of 0.04 are 19.78,14.77,23.83,60.53,64.94$/m2,respectively.The S5 system has the highest environmental effect with 3.04 t/m2 reduction of CO_(2) over 30 years of operation.
基金This work was sponsored by National Key Research and Development Project of China 2019YFA0906300 and 2020YFA0907304National Natural Science Foundation of China 21776083+3 种基金the Fok Ying Tong Education Foundation 161017Natural Science Foundation of Shandong Province ZR2019ZD17Natural Science Foundation of Shanghai 21ZR1416400 and 19ZR1472700the Fundamental Research Funds for the Central Universities 22221818014,Funding Project of the State Key Laboratory of Bioreactor Engineering.
文摘Cyanobacteria can utilize CO2 or even N2 to produce a variety of high value-added products efficiently.Plastoquinone(PQ)is an important electron carrier in both of the photosynthetic and respiratory electron transport chain.Although the content of PQ,as well as their redox state,have an important effect on physiology and metabolism,there are relatively few studies on the synthesis of PQ and its related metabolic regulation mechanism in photosynthetic microorganisms.In this study,the strategies of overexpression of Geranyl diphosphate:4-hydroxybenzoate geranyltransferase(lepgt)and addition of 4-hydroxybenzoate(4-HB)as the quinone ring precursor were adopted to regulate the biosynthesis of PQ in Synechocystis PCC 6803.Combined with the analysis the photosystem activity,respiration rate and metabolic components,we found the changes of intracellular PQ reprogrammed the metabolism of Synechocystis PCC 6803.The results showed that the overexpression of lepgt reduced PQ content dramatically,by 22.18%.Interestingly,both of the photosynthesis and respiration rate were enhanced.In addition,the intracellular lipid and protein contents were significantly increased.Whereas,the addition of low concentrations of 4-HB enhanced the biosynthesis of PQ,and the intracellular PQ contents were increased by 14.76%-70.86%in different conditions.Addition of 4-HB can regulate the photosystem efficiency and respiration and reprogram the metabolism of Synechocystis PCC 6803 efficiently.In a word,regulating the PQ biosynthesis provided a novel idea for promoting the reprogramming the physiology and metabolism of Synechocystis.
基金the National Natural Science Foundation of China(No.52078408,No.51908442)the State Key Program of National Natural Science Foundation of China(No.U20A20311)the Science Foundation for Outstanding Youth of Shaanxi Province(No.2020JC-43).
文摘It is necessary to satisfy the flexible requirements of solar heat storage systems to provide efficient heating and constant-temperature domestic hot water at different periods.A novel heat storage tank with both stratified and mixing functions is proposed,which can realize the integration of stable stratification and rapid mixing modes.In this research,a three-dimensional heat transfer model of the heat storage tank with stratified and mixed dual modes was established,and a thermal performance test system for the tank was built in the State Key Laboratory of Green Building in Western China.Moreover,a new evaluation index representing the mixing speed is proposed.The stratification effect and mixing characteristics of the tank were studied under different comprehensive conditions.The results show that the exergy efficiency of the tank with a stratified pipe can be increased by 10%–15%compared to that of a conventional tank.Additionally,the recommended optimal flow rate range for well-stratified tanks is 4–6 L/min.The mixing nozzle of the tank reduces the mixing reaction coefficient by 0.27 and significantly reduces the mixing time.This study provides critical guidance to meet the flexible thermal needs of users and implement high-performance applications using the stratified and mixing modes of heat storage tanks.
