Hawthorn(Crataegus pinnatifida)fruit peel color and seed hardness are key traits that significantly impact economic value.We present here the high-quality chromosome-scale genomes of two cultivars,including the hard-s...Hawthorn(Crataegus pinnatifida)fruit peel color and seed hardness are key traits that significantly impact economic value.We present here the high-quality chromosome-scale genomes of two cultivars,including the hard-seed,yellow-peel C.pinnatifida“Jinruyi”(JRY)and the soft-seed,red-peel C.pinnatifida“Ruanzi”(RZ).The assembled genomes comprising 17 chromosomes are 809.1 Mb and 760.5 Mb in size,achieving scaffold N50 values of 48.5 Mb and 46.8 Mb for JRY and RZ,respectively.Comparative genomic analysis identifies 3.6–3.8 million single nucleotide polymorphisms,8.5–9.3 million insertions/deletions,and approximately 30 Mb of presence/absence variations across different hawthorn genomes.Through integrating differentially expressed genes and accumulated metabolites,we filter candidate genes CpMYB114 and CpMYB44 associated with differences in hawthorn fruit peel color and seed hardness,respectively.Functional validation confirms that CpMYB114-CpANS regulates anthocyanin biosynthesis in hawthorn peels,contributing to the observed variation in peel color.CpMYB44-CpCOMT is significantly upregulated in JRY and has been shown to promote lignin biosynthesis,resulting in the distinction in seed hardness.Overall,this study reveals new insights into understanding of distinct peel pigmentation and seed hardness in hawthorn and provides an abundant resource for molecular breeding.展开更多
Flower senescence is commonly enhanced by the endogenous hormone ethylene and suppressed by the gibberellins(GAs)in plants.However,the detailed mechanisms for the antagonism of these hormones during f lower senescence...Flower senescence is commonly enhanced by the endogenous hormone ethylene and suppressed by the gibberellins(GAs)in plants.However,the detailed mechanisms for the antagonism of these hormones during f lower senescence remain elusive.In this study,we characterized one up-regulated gene PhOBF1,belonging to the basic leucine zipper transcription factor family,in senescing petals of petunia(Petunia hybrida).Exogenous treatments with ethylene and GA3 provoked a dramatic increase in PhOBF1 transcripts.Compared with wild-type plants,PhOBF1-RNAi transgenic petunia plants exhibited shortened f lower longevity,while overexpression of PhOBF1 resulted in delayed flower senescence.Transcript abundances of two senescence-related genes PhSAG12 and PhSAG29 were higher in PhOBF1-silenced plants but lower in PhOBF1-overexpressing plants.Silencing and overexpression of PhOBF1 affected expression levels of a few genes involved in the GA biosynthesis and signaling pathways,as well as accumulation levels of bioactive GAs GA1 and GA3.Application of GA3 restored the accelerated petal senescence to normal levels in PhOBF1-RNAi transgenic petunia lines,and reduced ethylene release and transcription of three ethylene biosynthetic genes PhACO1,PhACS1,and PhACS2.Moreover,PhOBF1 was observed to specifically bind to the PhGA20ox3 promoter containing a G-box motif.Transient silencing of PhGA20ox3 in petunia plants through tobacco rattle virus-based virus-induced gene silencing method led to accelerated corolla senescence.Our results suggest that PhOBF1 functions as a negative regulator of ethylene-mediated f lower senescence by modulating the GA production.展开更多
High temperature-humidity environment is one of the severe challenges in constructing Sichuan-Xizang railway tunnels.For enhancing construction efficiency and guaranteeing tunnel worker safety,addressing the high temp...High temperature-humidity environment is one of the severe challenges in constructing Sichuan-Xizang railway tunnels.For enhancing construction efficiency and guaranteeing tunnel worker safety,addressing the high temperature-humidity environment has irreplaceable significance.This study innovatively investigated the distribution law and evolution process of the thermal-humidity coupling field dur-ing tunnel construction.Besides,the corresponding ventilation measures were proposed based on the evaluation heat index(HI).If the initial temperature of the surrounding rock is constant,the distance between the ventilation duct outlet and the tunnel working face should not be greater than 30 m.Otherwise,the cooling performance of ventilation will be significantly weakened;If this temperature ranges in 65-85℃,the recommended ventilation velocity is 10-25 m/s,and the ventilation distance should not exceed 20 m.The con-clusions in this study are beneficial to better understand the high temperature-humidity environment in tunnel construction and can be a guideline for practical engineering application.展开更多
Switchable multi-layer ethylene tetra-fluoro-ethylene(ETFE)cushion controls the natural light and heat flux passing through the cushion with varying outdoor conditions by dynamically modifying its properties.In this p...Switchable multi-layer ethylene tetra-fluoro-ethylene(ETFE)cushion controls the natural light and heat flux passing through the cushion with varying outdoor conditions by dynamically modifying its properties.In this paper,the switchable ETFE cushions with ink printing of different optical and thermal properties were adopted as the window in a typical office model,and the indoor daylight and energy consumption were simulated by using Grasshopper software.Experimental model was built to validate the numerical model.Five locations representing five climate zones in China were selected to analyze the feasibility of the switchable ETFE cushion in different climates.The hourly indoor daylight and heat gain in a single day revealed the effects of the dynamic mechanism of ETFE cushion in improving indoor natural light and thermal environment.In addition,the annual daylight performance at the working area(1.5 m from the window)was simulated.ETFE cushion with printing of the lowest transmittance(ETFE1)was the optimal option for most cities and window-to-wall ratios,with the percentage of annual useful daylight hours up to 78.6%,except for the cases where the window-to-wall ratio(WWR)was 0.35 in Harbin,Beijing,and Hefei.The distribution of useful daylight hours revealed that ETFE cushions with low,medium,and high printing transmittance were suitable for offices where people work in the front,medium,and back region of the room,respectively.Energy consumption calculation revealed that ETFE1 showed advantages over other windows in most cities except for cities highly dominated by heating.ETFE1 delivered up to 33%of energy saving over a year in Kunming compared with the conventional double glazing but was not superior in cities with high heating and low cooling demands,such as Harbin.展开更多
Use of the longitudinal critical velocity in tunnel fires may destroy the stratification of smoke downstream,which is not conducive to the evacuation of downstream tunnel users.Reducing the longitudinal velocity can m...Use of the longitudinal critical velocity in tunnel fires may destroy the stratification of smoke downstream,which is not conducive to the evacuation of downstream tunnel users.Reducing the longitudinal velocity can maintain stratification,but the appropriate longitudinal velocity range is unknown.Stratification of smoke under the longitudinal velocity is studied using Fire Dynamics Simulator(FDS).The aims of this paper are to explore the relationship between the longitudinal velocity and smoke stratification and to obtain a proper velocity range that can maintain clear downstream stratification.Based on Newman's theory,the"stratification velocity"is proposed,which is the maximum velocity that maintains downstream smoke stratification.A good correspondence between the average Froude number within 200 m downstream and the longitudinal velocity and heat release rate(HRR)is found.The correlation between the temperature stratification and Froude number is obtained.Fr=0.49 can be used to distinguish whether the stratification is clear.The relationship between the critical velocity and the stratification velocity is also discussed.展开更多
The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro ...The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro pressure wave.Aerodynamic effects of tunnels will result in a significant increase in train energy consump-tion,shorten life of railway train/tunnel system,and increase maintenance cost.This paper provides a review of aerodynamics of railway train/tunnel system.Challenges in railway train/tunnel system aerodynamics and their related factors are discussed firstly.Aerodynamic performance and flow field characteristics of trains in tunnels are presented.Relationship of aerodynamic effects and parameters of railway train/tunnel system,and the control methods for reducing aerodynamic effects in tunnels are explained.A traffic safety evaluation of the train in tunnels,such as vehicle body structure,passengers’ear comfort,etc.,is introduced and analysed.Finally,future outlooks and research topics are proposed.展开更多
In this work,a series of nanoencapsulated phase change materials(NanoPCMs)with paraffin wax(PW)as core and melamine-formaldehyde(MF)as shell were synthesized by the in-situ polymerization method.The morphol-ogy,chemic...In this work,a series of nanoencapsulated phase change materials(NanoPCMs)with paraffin wax(PW)as core and melamine-formaldehyde(MF)as shell were synthesized by the in-situ polymerization method.The morphol-ogy,chemical structure and thermal properties of prepared NanoPCMs were characterized by scanning electron microscope,Fourier transform infrared,differential scanning calorimetry and thermogravimertic analyzer.The results show that the PW is successfully encapsulated in the MF without chemical interaction,and the NanoPCMs present regular spherical shape with the average diameter of 260-450 nm.The encapsulation efficiency of the NanoPCMs increases with the augment of the supplied amount of core material.The maximum encapsulation efficiency of the NanoPCMs can reach up to approximately 75%.The NanoPCMs can maintain excellent thermal reliability and stability after 2000 thermal cycling.The prepared NanoPCMs can be well applied in the latent heat thermal energy storage and thermal management systems due to their remarkable encapsulation efficiency and thermal properties enable them to.展开更多
To the Editor:Patients with type 2 diabetes have a higher risk of cardiovascular diseases(CVD),relative to people without diabetes.Patients with diabetes always exhibit lipid abnormalities.Rapid economic development a...To the Editor:Patients with type 2 diabetes have a higher risk of cardiovascular diseases(CVD),relative to people without diabetes.Patients with diabetes always exhibit lipid abnormalities.Rapid economic development and accelerated urbanization have also led to lifestyle changes that may have an influence on the lipid parameters of Chinese patients with diabetes.Given the significant differences in socioeconomic status in China,geographical variations were also observed in the prevalence,awareness,treatment,and control of dyslipidemia among individuals who were≥45 years old in the general Chinese population.[1]There is a lack of large-scale studies regarding time trends and geographical variations in lipid concentrations and lipid control among Chinese adults with type 2 diabetes.Therefore,we conducted a study on time trends and geographical variations in lipid concentrations and lipid control in this population using the China National HbA1c Surveillance System(CNHSS)database of adult Chinese outpatients with type 2 diabetes during 2009 to 2013.The Ethics Committee of the Chinese People Liberation Army General Hospital approved the study protocol.Informed consent was obtained from all the patients before they were interviewed and data collected.展开更多
Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions.Existing solar indirect-expansion systems connect the solar panels and evaporator of t...Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions.Existing solar indirect-expansion systems connect the solar panels and evaporator of the heat pump in parallel with the heat storage tank.For our system these three components are instead connected in series,which can stabilize the temperature at the inlet of the evaporator and decrease the inlet temperature of the solar panels,leading to improved energy efficiency and the production of much more thermal energy.The experimental results of this system show that the average electrical,thermal and overall efficiency of the PV/T panels are 15.9%,33.4%and 49.3%,respectively.The average thermal efficiency of the thermal panels is 60.4%,the COP of heat pump is 4.7 and the room temperature is constantly over 18°C.Based on the experimental results,some improvements are analyzed.We conclude that this operating model can meet the requirement of space heating in low solar radiation environments.展开更多
Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysi...Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysis,combustion,and fire spread process are different from those fire accidents in open space.Identifying the fire characteristics of the railway train carriages is the key issue to determine the fire prevention and control strategy.Therefore,this paper attempts to assess and identify the characteristics of pyrolysis,combustion,and fire spread of railway trains based on the exising research.This review documents the pyrolysis and combustion characteristics of single train material and the combustible module,summarizes the heat release rate(HRR)calculation methods and the HRR profile for different types of trains,as well as introduces the research progress in the flame spread and flashover.The main gaps and issues to be solved in terms of the effects of train speed,altitudes,and application of new energy trains are further discussed.展开更多
Thermal comfort is critical for ensuring the health and productivity of occupants and knowing their thermal demand could help creat a satisfying environment with the least energy waste.Theory of thermal comfort is bui...Thermal comfort is critical for ensuring the health and productivity of occupants and knowing their thermal demand could help creat a satisfying environment with the least energy waste.Theory of thermal comfort is built based on experimental studies in uniform and stable environments,while there is still a gap when applying in evaluating human thermal comfort in non-uniform thermal environments.Therefore,an insight into human thermal comfort in non-uniform thermal environments is taken.The fundamental studies of thermal comfort in non-uniform thermal environments are explicated,including thermal comfort theory applied in non-uniform thermal environments,types of non-uniform thermal environments and corresponding studies,physiological and psychological thermal responses in the environments.Besides,the evaluation indices of non-uniform thermal environments are classified according to their definitions and the comfort models are reviewed.Finally,future works in this research field are discussed.In general,the overall thermal comfort and local thermal comfort should be both taken into account in non-uniform thermal environments where skin temperatures and psychological thermal responses of occupants are different among local body segments.Moreover,as studies of local thermal comfort are mainly conducted in thermally neutral condition,the limits considering the state deviating thermal neutrality(slightly warm or cool),which is frequently found in reality,are encouraged to be studied.Finally,a well-defined comprehensive index should be proposed considering heat exchange of human body with their microenvironments and thus the comfort range of the index could be provided for designing of non-uniform thermal environments.展开更多
Renewable energy technologies,particularly in electric vehicles(EVs),have received significant attention in re-cent years.The wasted energy in a vehicle’s shock absorber can be converted into an alternative energy so...Renewable energy technologies,particularly in electric vehicles(EVs),have received significant attention in re-cent years.The wasted energy in a vehicle’s shock absorber can be converted into an alternative energy source by regenerative shock absorbers.In this paper,a high-efficiency regenerative shock absorber considering twin ball screws transmissions is proposed for application in range-extended electric vehicles.The proposed regenerative shock absorber can convert vibrational kinetic energy,which is traditionally dissipated as heat in suspension systems,into electricity.The proposed system is divided into four modules:suspension vibration input module,transmission module,generator module and power storage module.Induced by road roughness,the irregular linear oscillations of the suspension are transmitted to the suspension vibration input module.The reciprocating vibrations are converted into unidirectional rotation of the generator by a pair of ball screws,gears,and two overrun clutches in the transmission module.The utilisation of different screw pitches leads to different damping coefficients for upward and downward progress,enabling the shock absorber to fully utilise elastic elements to im-prove vehicle comfort when compressed and quickly absorb vibrations when stretched.The electricity produced by the generator is stored in supercapacitors to charge the battery and extend the range of EVs.The mechanical properties of the full-scaled fabricated prototype were studied by utilising a mechanical testing and sensing fix-ture.An average power output of 3.701 W in 1Hz-3 mm sinusoidal vibration input and a peak efficiency of 51.1%and average efficiency of 36.4%were achieved in a bench tests.The range can be approximately extended by 1 mile per 100 miles when EV is driving on the road of class B with a speed of 60 km/h,demonstrating that the proposed high-efficiency regenerative shock absorber is beneficial for harvesting renewable energy,and practical and significant for extending the range of EVs.展开更多
Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-fr...Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-friendliness.This paper elaborates the operational principles and technical properties and summarizes the appli-cability of elastic energy storage technology with spiral springs.Elastic energy storage using spiral spring can realize the balance between energy supply and demand in some applications.Continuous input-spontaneous out-put working style can provide simple energy sources for short-time energy supply,and provide strong moment impact and rapid start,or realize the energy conservation for reciprocating movement.Uniform output working style can realize energy output with uniform speed for timekeeping and load-driving.Random input working style can harvest and store random mechanical energy or convert small torque into a large moment to drive external loads.Finally,this paper proposes new researches and developments of elastic energy storage technology on new materials and structures,mechanical properties and structural dynamics analyses,design and control for new functions.展开更多
During the operation of the capillary heat exchange system in the metro tunnel,the pipe length,pipe spacing and air velocity have different effects on the heat transfer effect and show certain rules.Taking Kunming as ...During the operation of the capillary heat exchange system in the metro tunnel,the pipe length,pipe spacing and air velocity have different effects on the heat transfer effect and show certain rules.Taking Kunming as an example,a single-factor analysis method was used to establish multiple-capillary model,and the variation of different influencing factors in the heat transfer process was obtained.On this basis,a single-capillary model was established to analyze the thermal interference variation of the pipe spacing between the two models.Under the condition of ensuring the capillary outlet water temperature and heat flux,the relevant parameters of the capillary heat exchanger were optimized.The results show that the pipe length of the capillary heat exchanger should be kept within 3-5 m,the pipe spacing is maintained at 20-30 mm,and the capillary heat exchanger of each set can be operated in parallel to ensure that heat exchanger have better heat transfer performance.During the system stop running,the air velocity in winter and summer has different effects on the recovery of surrounding rock.展开更多
The effect of Cu content on the high temperature oxidation properties of the phase change material(PCM)Al-Cu-Si alloys was studied.The oxidation kinetics curves at 600◦C were achieved for Al-Cu-Si alloys with 35-55%Cu...The effect of Cu content on the high temperature oxidation properties of the phase change material(PCM)Al-Cu-Si alloys was studied.The oxidation kinetics curves at 600◦C were achieved for Al-Cu-Si alloys with 35-55%Cu,which all follow the cubic law.With an increase in the Cu content from 35 to 55%,the weight gain decreases from 5.75 to 3×10^(−4) g/cm^(2) after 96 h isothermal oxidation.The oxidation rate also decreases with Cu content,the maximum and minimum rates are 1.52 and 0.32×10^(−5) g/cm^(2)•h,a nearly 4 times difference.Oxidation does not change the phase composition of Al-Cu-Si alloys,but coarsens the microstructure.The latent heat and the starting temperature of phase change after 96 h oxidation at 600◦C have variations of less than 10%and 6◦C,respectively,indicating that the Al-Cu-Si alloys have good thermal stability after high temperature oxidation.展开更多
The International Conference for Global Chinese Academia on Energy and Built Environment(ICCEBE)is a premier international event covering a broad range of topics on clean energy utilization,energy efficiency and envir...The International Conference for Global Chinese Academia on Energy and Built Environment(ICCEBE)is a premier international event covering a broad range of topics on clean energy utilization,energy efficiency and environmental quality in the built environment.The conference aims to provide a forum to share cutting-edge achievements in the built environment,and to promote academic collaboration and cooperation among worldwide Chinese scholars.展开更多
In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This ...In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.The system includes a photovoltaic power generation module and an electricity transfer module.The photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.The electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were conducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.The results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system.展开更多
Renewable paper reusing plays a significant role in the sustainable environment under the background of the shortage in forest resources and the pollution from the paper industry.The conventional reusing stream of was...Renewable paper reusing plays a significant role in the sustainable environment under the background of the shortage in forest resources and the pollution from the paper industry.The conventional reusing stream of waste office paper appears to have low reusing rates while consuming massive amounts of energy in intermediate steps.In this study,we developed a novel portable renewable desktop paper reusing system based on font area detection and greyscale sensor.The proposed system consists of two main parts,namely,a greyscale sensor and font area detection model and a polishing mechanism.Acting as an ink mark detector for waste desktop paper,the greyscale sensor and font area detection model can detect the font in the waste desktop paper using an adaptive dynamic compensation schematic.The polishing mechanism will grind the font area of the wasted desktop paper,and this paper reusing processing is non-chemical,energy saving and environmentally friendly.The proposed system is demonstrated through simulations and experimental results,which show that the proposed renewable desktop paper reusing system is portable and is effective for reusing waste office paper in the office.An accuracy of 99.78%is demonstrated in the greyscale sensor and font area detection model,and the average reuse rate of one piece of paper is 2.52 times,verifying that the proposed portable system is effective and practical in renewable desktop paper reusing applications.展开更多
基金supported by grants from the National Natural Science Foundation of China(32401631)Beijing Academy of Agriculture and Forestry Science Innovation Capability Construction Special Project(KJCX20251401)+1 种基金Research Fund for Youth of Beijing Academy of Agricultural and Forestry Science(QNJJ202409)Youth Research Foundation of Institute of Forestry and Pomology,Beijing Academy of Agriculture and Forestry Science(LGSJJ202302).
文摘Hawthorn(Crataegus pinnatifida)fruit peel color and seed hardness are key traits that significantly impact economic value.We present here the high-quality chromosome-scale genomes of two cultivars,including the hard-seed,yellow-peel C.pinnatifida“Jinruyi”(JRY)and the soft-seed,red-peel C.pinnatifida“Ruanzi”(RZ).The assembled genomes comprising 17 chromosomes are 809.1 Mb and 760.5 Mb in size,achieving scaffold N50 values of 48.5 Mb and 46.8 Mb for JRY and RZ,respectively.Comparative genomic analysis identifies 3.6–3.8 million single nucleotide polymorphisms,8.5–9.3 million insertions/deletions,and approximately 30 Mb of presence/absence variations across different hawthorn genomes.Through integrating differentially expressed genes and accumulated metabolites,we filter candidate genes CpMYB114 and CpMYB44 associated with differences in hawthorn fruit peel color and seed hardness,respectively.Functional validation confirms that CpMYB114-CpANS regulates anthocyanin biosynthesis in hawthorn peels,contributing to the observed variation in peel color.CpMYB44-CpCOMT is significantly upregulated in JRY and has been shown to promote lignin biosynthesis,resulting in the distinction in seed hardness.Overall,this study reveals new insights into understanding of distinct peel pigmentation and seed hardness in hawthorn and provides an abundant resource for molecular breeding.
基金funded by the National Natural Science Foundation of China(Grant no.32271953 and 31801895)Postdoctoral Special Funding Project of China(Grant no.2019T120958)the Basic Scientific Research Expense of Northwest A&F University(Grant no.Z1090322159).
文摘Flower senescence is commonly enhanced by the endogenous hormone ethylene and suppressed by the gibberellins(GAs)in plants.However,the detailed mechanisms for the antagonism of these hormones during f lower senescence remain elusive.In this study,we characterized one up-regulated gene PhOBF1,belonging to the basic leucine zipper transcription factor family,in senescing petals of petunia(Petunia hybrida).Exogenous treatments with ethylene and GA3 provoked a dramatic increase in PhOBF1 transcripts.Compared with wild-type plants,PhOBF1-RNAi transgenic petunia plants exhibited shortened f lower longevity,while overexpression of PhOBF1 resulted in delayed flower senescence.Transcript abundances of two senescence-related genes PhSAG12 and PhSAG29 were higher in PhOBF1-silenced plants but lower in PhOBF1-overexpressing plants.Silencing and overexpression of PhOBF1 affected expression levels of a few genes involved in the GA biosynthesis and signaling pathways,as well as accumulation levels of bioactive GAs GA1 and GA3.Application of GA3 restored the accelerated petal senescence to normal levels in PhOBF1-RNAi transgenic petunia lines,and reduced ethylene release and transcription of three ethylene biosynthetic genes PhACO1,PhACS1,and PhACS2.Moreover,PhOBF1 was observed to specifically bind to the PhGA20ox3 promoter containing a G-box motif.Transient silencing of PhGA20ox3 in petunia plants through tobacco rattle virus-based virus-induced gene silencing method led to accelerated corolla senescence.Our results suggest that PhOBF1 functions as a negative regulator of ethylene-mediated f lower senescence by modulating the GA production.
基金the National Natural Science Foundation of China(Grant No.52038009),and one anonymous reviewer is acknowledged for the valuable comments.
文摘High temperature-humidity environment is one of the severe challenges in constructing Sichuan-Xizang railway tunnels.For enhancing construction efficiency and guaranteeing tunnel worker safety,addressing the high temperature-humidity environment has irreplaceable significance.This study innovatively investigated the distribution law and evolution process of the thermal-humidity coupling field dur-ing tunnel construction.Besides,the corresponding ventilation measures were proposed based on the evaluation heat index(HI).If the initial temperature of the surrounding rock is constant,the distance between the ventilation duct outlet and the tunnel working face should not be greater than 30 m.Otherwise,the cooling performance of ventilation will be significantly weakened;If this temperature ranges in 65-85℃,the recommended ventilation velocity is 10-25 m/s,and the ventilation distance should not exceed 20 m.The con-clusions in this study are beneficial to better understand the high temperature-humidity environment in tunnel construction and can be a guideline for practical engineering application.
基金supported by grants from the Key Research and Development Program of Anhui Province(No.S202004a07020029)National Natural Science Foundation of China(No.51908174)Anhui Provincial Natural Science Foundation(No.1908085QE206).
文摘Switchable multi-layer ethylene tetra-fluoro-ethylene(ETFE)cushion controls the natural light and heat flux passing through the cushion with varying outdoor conditions by dynamically modifying its properties.In this paper,the switchable ETFE cushions with ink printing of different optical and thermal properties were adopted as the window in a typical office model,and the indoor daylight and energy consumption were simulated by using Grasshopper software.Experimental model was built to validate the numerical model.Five locations representing five climate zones in China were selected to analyze the feasibility of the switchable ETFE cushion in different climates.The hourly indoor daylight and heat gain in a single day revealed the effects of the dynamic mechanism of ETFE cushion in improving indoor natural light and thermal environment.In addition,the annual daylight performance at the working area(1.5 m from the window)was simulated.ETFE cushion with printing of the lowest transmittance(ETFE1)was the optimal option for most cities and window-to-wall ratios,with the percentage of annual useful daylight hours up to 78.6%,except for the cases where the window-to-wall ratio(WWR)was 0.35 in Harbin,Beijing,and Hefei.The distribution of useful daylight hours revealed that ETFE cushions with low,medium,and high printing transmittance were suitable for offices where people work in the front,medium,and back region of the room,respectively.Energy consumption calculation revealed that ETFE1 showed advantages over other windows in most cities except for cities highly dominated by heating.ETFE1 delivered up to 33%of energy saving over a year in Kunming compared with the conventional double glazing but was not superior in cities with high heating and low cooling demands,such as Harbin.
基金supported by the Sichuan Province Youth Science and Technology Innovation Team of Building Environment and Energy Efficiency(2015TD0015)the National Natural Science Foundation of China(Grant No.51708454).
文摘Use of the longitudinal critical velocity in tunnel fires may destroy the stratification of smoke downstream,which is not conducive to the evacuation of downstream tunnel users.Reducing the longitudinal velocity can maintain stratification,but the appropriate longitudinal velocity range is unknown.Stratification of smoke under the longitudinal velocity is studied using Fire Dynamics Simulator(FDS).The aims of this paper are to explore the relationship between the longitudinal velocity and smoke stratification and to obtain a proper velocity range that can maintain clear downstream stratification.Based on Newman's theory,the"stratification velocity"is proposed,which is the maximum velocity that maintains downstream smoke stratification.A good correspondence between the average Froude number within 200 m downstream and the longitudinal velocity and heat release rate(HRR)is found.The correlation between the temperature stratification and Froude number is obtained.Fr=0.49 can be used to distinguish whether the stratification is clear.The relationship between the critical velocity and the stratification velocity is also discussed.
基金supported by the National Natural Science Foun-dation of China(51805453,51978575,and 51975487)the Funda-mental Research Funds for the Central Universities(2682018CX14)the Project funded by China Postdoctoral Science Foundation(2019M663551).
文摘The coupling and complexity of railway train/tunnel system are further aggravated by increasing train speed,which produces a series of aerodynamics problems,such as aerodynamic drag,slipstream,pressure wave and micro pressure wave.Aerodynamic effects of tunnels will result in a significant increase in train energy consump-tion,shorten life of railway train/tunnel system,and increase maintenance cost.This paper provides a review of aerodynamics of railway train/tunnel system.Challenges in railway train/tunnel system aerodynamics and their related factors are discussed firstly.Aerodynamic performance and flow field characteristics of trains in tunnels are presented.Relationship of aerodynamic effects and parameters of railway train/tunnel system,and the control methods for reducing aerodynamic effects in tunnels are explained.A traffic safety evaluation of the train in tunnels,such as vehicle body structure,passengers’ear comfort,etc.,is introduced and analysed.Finally,future outlooks and research topics are proposed.
基金supported by the National Key Research and Develop-ment Program of China(Grant No.2018YFC0705306)the Chengdu Sci-ence and Technology Project(No:2019-YF05-01332-SN)the Na-tional Natural Science Foundation of China(No:51678488).
文摘In this work,a series of nanoencapsulated phase change materials(NanoPCMs)with paraffin wax(PW)as core and melamine-formaldehyde(MF)as shell were synthesized by the in-situ polymerization method.The morphol-ogy,chemical structure and thermal properties of prepared NanoPCMs were characterized by scanning electron microscope,Fourier transform infrared,differential scanning calorimetry and thermogravimertic analyzer.The results show that the PW is successfully encapsulated in the MF without chemical interaction,and the NanoPCMs present regular spherical shape with the average diameter of 260-450 nm.The encapsulation efficiency of the NanoPCMs increases with the augment of the supplied amount of core material.The maximum encapsulation efficiency of the NanoPCMs can reach up to approximately 75%.The NanoPCMs can maintain excellent thermal reliability and stability after 2000 thermal cycling.The prepared NanoPCMs can be well applied in the latent heat thermal energy storage and thermal management systems due to their remarkable encapsulation efficiency and thermal properties enable them to.
基金This work was supported by the Major Chronic Noncommunicable Disease Prevention and Control Research and the National Key Research and Development Program of China(Nos.2016YFC1305600 and 2016YFC1305603)。
文摘To the Editor:Patients with type 2 diabetes have a higher risk of cardiovascular diseases(CVD),relative to people without diabetes.Patients with diabetes always exhibit lipid abnormalities.Rapid economic development and accelerated urbanization have also led to lifestyle changes that may have an influence on the lipid parameters of Chinese patients with diabetes.Given the significant differences in socioeconomic status in China,geographical variations were also observed in the prevalence,awareness,treatment,and control of dyslipidemia among individuals who were≥45 years old in the general Chinese population.[1]There is a lack of large-scale studies regarding time trends and geographical variations in lipid concentrations and lipid control among Chinese adults with type 2 diabetes.Therefore,we conducted a study on time trends and geographical variations in lipid concentrations and lipid control in this population using the China National HbA1c Surveillance System(CNHSS)database of adult Chinese outpatients with type 2 diabetes during 2009 to 2013.The Ethics Committee of the Chinese People Liberation Army General Hospital approved the study protocol.Informed consent was obtained from all the patients before they were interviewed and data collected.
文摘Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions.Existing solar indirect-expansion systems connect the solar panels and evaporator of the heat pump in parallel with the heat storage tank.For our system these three components are instead connected in series,which can stabilize the temperature at the inlet of the evaporator and decrease the inlet temperature of the solar panels,leading to improved energy efficiency and the production of much more thermal energy.The experimental results of this system show that the average electrical,thermal and overall efficiency of the PV/T panels are 15.9%,33.4%and 49.3%,respectively.The average thermal efficiency of the thermal panels is 60.4%,the COP of heat pump is 4.7 and the room temperature is constantly over 18°C.Based on the experimental results,some improvements are analyzed.We conclude that this operating model can meet the requirement of space heating in low solar radiation environments.
基金The authors wish to thank the financial support of the National Nat-ural Science Foundation of China,No.52038009.
文摘Fires in the railway trains are prone to cause large numbers of casualties,serious economic losses,and huge negative social impacts.The railway train carriage is a special confined built environment,where the pyrolysis,combustion,and fire spread process are different from those fire accidents in open space.Identifying the fire characteristics of the railway train carriages is the key issue to determine the fire prevention and control strategy.Therefore,this paper attempts to assess and identify the characteristics of pyrolysis,combustion,and fire spread of railway trains based on the exising research.This review documents the pyrolysis and combustion characteristics of single train material and the combustible module,summarizes the heat release rate(HRR)calculation methods and the HRR profile for different types of trains,as well as introduces the research progress in the flame spread and flashover.The main gaps and issues to be solved in terms of the effects of train speed,altitudes,and application of new energy trains are further discussed.
基金supported by the National Natural Science Foundation of China(Grant No.52038009)the Fundamental Research Funds for the Central Universities(2682023CX028)Southwest Jiaotong University(R110223H01004).
文摘Thermal comfort is critical for ensuring the health and productivity of occupants and knowing their thermal demand could help creat a satisfying environment with the least energy waste.Theory of thermal comfort is built based on experimental studies in uniform and stable environments,while there is still a gap when applying in evaluating human thermal comfort in non-uniform thermal environments.Therefore,an insight into human thermal comfort in non-uniform thermal environments is taken.The fundamental studies of thermal comfort in non-uniform thermal environments are explicated,including thermal comfort theory applied in non-uniform thermal environments,types of non-uniform thermal environments and corresponding studies,physiological and psychological thermal responses in the environments.Besides,the evaluation indices of non-uniform thermal environments are classified according to their definitions and the comfort models are reviewed.Finally,future works in this research field are discussed.In general,the overall thermal comfort and local thermal comfort should be both taken into account in non-uniform thermal environments where skin temperatures and psychological thermal responses of occupants are different among local body segments.Moreover,as studies of local thermal comfort are mainly conducted in thermally neutral condition,the limits considering the state deviating thermal neutrality(slightly warm or cool),which is frequently found in reality,are encouraged to be studied.Finally,a well-defined comprehensive index should be proposed considering heat exchange of human body with their microenvironments and thus the comfort range of the index could be provided for designing of non-uniform thermal environments.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.51675451 and 51975490Science and Tech-nology Projects of Sichuan and Chengdu under Grant Nos.2016GZ0026,2016CC0027,2017RZ0056,and 18MZGC0272.
文摘Renewable energy technologies,particularly in electric vehicles(EVs),have received significant attention in re-cent years.The wasted energy in a vehicle’s shock absorber can be converted into an alternative energy source by regenerative shock absorbers.In this paper,a high-efficiency regenerative shock absorber considering twin ball screws transmissions is proposed for application in range-extended electric vehicles.The proposed regenerative shock absorber can convert vibrational kinetic energy,which is traditionally dissipated as heat in suspension systems,into electricity.The proposed system is divided into four modules:suspension vibration input module,transmission module,generator module and power storage module.Induced by road roughness,the irregular linear oscillations of the suspension are transmitted to the suspension vibration input module.The reciprocating vibrations are converted into unidirectional rotation of the generator by a pair of ball screws,gears,and two overrun clutches in the transmission module.The utilisation of different screw pitches leads to different damping coefficients for upward and downward progress,enabling the shock absorber to fully utilise elastic elements to im-prove vehicle comfort when compressed and quickly absorb vibrations when stretched.The electricity produced by the generator is stored in supercapacitors to charge the battery and extend the range of EVs.The mechanical properties of the full-scaled fabricated prototype were studied by utilising a mechanical testing and sensing fix-ture.An average power output of 3.701 W in 1Hz-3 mm sinusoidal vibration input and a peak efficiency of 51.1%and average efficiency of 36.4%were achieved in a bench tests.The range can be approximately extended by 1 mile per 100 miles when EV is driving on the road of class B with a speed of 60 km/h,demonstrating that the proposed high-efficiency regenerative shock absorber is beneficial for harvesting renewable energy,and practical and significant for extending the range of EVs.
基金Thanks to Sichuan Province Innovation Team Project for Building Environment and Energy Efficient Utilization(No:2015TD0015)Major Project Engagement Fund of Southwest Jiaotong University,and Funda-mental Research Funds for the Central Universities(2682014CX014EM)for their financial aids.
文摘Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-friendliness.This paper elaborates the operational principles and technical properties and summarizes the appli-cability of elastic energy storage technology with spiral springs.Elastic energy storage using spiral spring can realize the balance between energy supply and demand in some applications.Continuous input-spontaneous out-put working style can provide simple energy sources for short-time energy supply,and provide strong moment impact and rapid start,or realize the energy conservation for reciprocating movement.Uniform output working style can realize energy output with uniform speed for timekeeping and load-driving.Random input working style can harvest and store random mechanical energy or convert small torque into a large moment to drive external loads.Finally,this paper proposes new researches and developments of elastic energy storage technology on new materials and structures,mechanical properties and structural dynamics analyses,design and control for new functions.
基金This work was supported by the Natural Science Foundation of China(Grant No.51678488).
文摘During the operation of the capillary heat exchange system in the metro tunnel,the pipe length,pipe spacing and air velocity have different effects on the heat transfer effect and show certain rules.Taking Kunming as an example,a single-factor analysis method was used to establish multiple-capillary model,and the variation of different influencing factors in the heat transfer process was obtained.On this basis,a single-capillary model was established to analyze the thermal interference variation of the pipe spacing between the two models.Under the condition of ensuring the capillary outlet water temperature and heat flux,the relevant parameters of the capillary heat exchanger were optimized.The results show that the pipe length of the capillary heat exchanger should be kept within 3-5 m,the pipe spacing is maintained at 20-30 mm,and the capillary heat exchanger of each set can be operated in parallel to ensure that heat exchanger have better heat transfer performance.During the system stop running,the air velocity in winter and summer has different effects on the recovery of surrounding rock.
基金The work is supported by the Chengdu Science and Technology Project(No:2019-YF05-01332-SN)the National Natural Science Foundation of China(No:51678488).
文摘The effect of Cu content on the high temperature oxidation properties of the phase change material(PCM)Al-Cu-Si alloys was studied.The oxidation kinetics curves at 600◦C were achieved for Al-Cu-Si alloys with 35-55%Cu,which all follow the cubic law.With an increase in the Cu content from 35 to 55%,the weight gain decreases from 5.75 to 3×10^(−4) g/cm^(2) after 96 h isothermal oxidation.The oxidation rate also decreases with Cu content,the maximum and minimum rates are 1.52 and 0.32×10^(−5) g/cm^(2)•h,a nearly 4 times difference.Oxidation does not change the phase composition of Al-Cu-Si alloys,but coarsens the microstructure.The latent heat and the starting temperature of phase change after 96 h oxidation at 600◦C have variations of less than 10%and 6◦C,respectively,indicating that the Al-Cu-Si alloys have good thermal stability after high temperature oxidation.
文摘The International Conference for Global Chinese Academia on Energy and Built Environment(ICCEBE)is a premier international event covering a broad range of topics on clean energy utilization,energy efficiency and environmental quality in the built environment.The conference aims to provide a forum to share cutting-edge achievements in the built environment,and to promote academic collaboration and cooperation among worldwide Chinese scholars.
基金supported by the National Natural Science Foundation of China under grants no.51975490the Science and Technology Projects of Sichuan under grant nos.2021JDRC0118,2021JDRC0096,2021YFSY0059,and 2021YFQ0055.
文摘In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.The system includes a photovoltaic power generation module and an electricity transfer module.The photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.The electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were conducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.The results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system.
基金This work was supported by the National Natural Science Founda-tion of China under Grant Nos.51675451 and 51975490by the Science and Technology Projects of Sichuan under Grant Nos.19MZGC0116,19MZGC0117 and 19MZGC0110.
文摘Renewable paper reusing plays a significant role in the sustainable environment under the background of the shortage in forest resources and the pollution from the paper industry.The conventional reusing stream of waste office paper appears to have low reusing rates while consuming massive amounts of energy in intermediate steps.In this study,we developed a novel portable renewable desktop paper reusing system based on font area detection and greyscale sensor.The proposed system consists of two main parts,namely,a greyscale sensor and font area detection model and a polishing mechanism.Acting as an ink mark detector for waste desktop paper,the greyscale sensor and font area detection model can detect the font in the waste desktop paper using an adaptive dynamic compensation schematic.The polishing mechanism will grind the font area of the wasted desktop paper,and this paper reusing processing is non-chemical,energy saving and environmentally friendly.The proposed system is demonstrated through simulations and experimental results,which show that the proposed renewable desktop paper reusing system is portable and is effective for reusing waste office paper in the office.An accuracy of 99.78%is demonstrated in the greyscale sensor and font area detection model,and the average reuse rate of one piece of paper is 2.52 times,verifying that the proposed portable system is effective and practical in renewable desktop paper reusing applications.
