Many people like to shop at a supermarket.Supermarkets are very convenient.They are open long hours,every day of the week.Everything is easy to find in a supermarket.It's always in the same place.Supermarkets ofte...Many people like to shop at a supermarket.Supermarkets are very convenient.They are open long hours,every day of the week.Everything is easy to find in a supermarket.It's always in the same place.Supermarkets often have sales.These can help you save money.展开更多
好题精选阅读下面短文,从每题所给的A、B、C、D四个选项中选出最佳选项。Born during my parents'sea voyage(航行)around the world,I always wanted to make the trip myself.At age 8,I began saving and sailing to 1 that drea...好题精选阅读下面短文,从每题所给的A、B、C、D四个选项中选出最佳选项。Born during my parents'sea voyage(航行)around the world,I always wanted to make the trip myself.At age 8,I began saving and sailing to 1 that dream.My parents weren't excited about the idea,but after talking to them about it,they became 2.展开更多
As an indispensable part of modern buildings,centralized central air conditioning systems play an important role in maintaining the comfort and air quality of the indoor environment.However,with the increasing energy ...As an indispensable part of modern buildings,centralized central air conditioning systems play an important role in maintaining the comfort and air quality of the indoor environment.However,with the increasing energy consumption,how to improve the energy efficiency ratio of air conditioning systems and reduce energy consumption has become an important issue in research and practice.The purpose of this paper is to discuss the impact of humidity control strategies on energy saving in centralized central air conditioning systems,with a view to providing a theoretical basis and practical guidance for realizing building energy efficiency.展开更多
Load-sensing systems use a centralized power source for energy supply and multiway valves for flow distribution and suffer from excessive throttling losses and low energy efficiency.Pump-controlled systems adopt volum...Load-sensing systems use a centralized power source for energy supply and multiway valves for flow distribution and suffer from excessive throttling losses and low energy efficiency.Pump-controlled systems adopt volumetric control methods to eliminate throttling losses.However,pump-controlled multi-actuator systems require excessive installed power.To address these issues,by combining the respective advantages of valve-and pump-controlled technologies,an open-closed circuit integrated pump-valve collaborative drive multi-actuator system consisting of pump-and valve-controlled units is proposed.The pump-controlled units manage the individual actuator motions,whereas the valve-controlled unit enhances the driving power of the pump-controlled units.In addition,to optimize the operation characteristics and energy consumption,a four-quadrant control strategy and an ultralow-pressure loss control strategy were proposed.Several experiments were conducted to evaluate the working performance of the proposed system and the load-sensing system under different working conditions.Experimental results demonstrated that the proposed system exhibited satisfactory velocity control characteristics.Compared with the traditional load-sensing system,the proposed system reduced throttling losses by 90.4−94.4%and energy consumption by 45.9−50.0%.Additionally,only 22.8%of the total energy consumption was attributed to the pump-controlled units,with the remainder provided by the valve-controlled unit.Compared with the traditional pump-controlled multi-actuator system,the proposed system achieved a 29.4%reduction in installed power,thereby lowering the system installed power and costs.This paper presents an electrohydraulic multi-actuator drive method that combines high energy efficiency and high power density and is suitable for electric construction machinery and other heavy equipment with multiple actuators.展开更多
Jinmao Tex(short for Chongqing Jinmao Textile Accessories Co.,Ltd.),founded in 1960,is the largest manufacturer of ring traveller and steel ring in China,and its ring traveller delivery tops in China market for more t...Jinmao Tex(short for Chongqing Jinmao Textile Accessories Co.,Ltd.),founded in 1960,is the largest manufacturer of ring traveller and steel ring in China,and its ring traveller delivery tops in China market for more than 30 consecutive years.In recent years,in order to serve the transformation and upgrading of the textile industry,Jinmao Tex invested"China Ring Traveller and Steel Ring R&D center",focused on the technological innovation of key textile accessories,developed high-performance and long-life textile accessories to assist textile mills save energy,reduce consumption,improve quality and increase efficiency.Jinmao Tex has now become a“steel ring+ring traveller”solution provider for high-speed spinning and differential fiber spinning.展开更多
Heating,ventilation,and air conditioning(HVAC)systems contribute substantially to global energy consumption,while rejecting significant amounts of low-grade heat into the environment.This paper presents a nonintrusive...Heating,ventilation,and air conditioning(HVAC)systems contribute substantially to global energy consumption,while rejecting significant amounts of low-grade heat into the environment.This paper presents a nonintrusive spiral-coil heat exchanger designed to recover waste heat from the outdoor condenser of a split-type air conditioner.The system operates externally without altering the existing HVAC configuration,thereby rendering it suitable for retrofitting.Water was circulated as the working fluid at flow rates of 0.028–0.052 kg/s to assess thermal performance.Performance indicators,including the outlet water temperature,heat transfer rate,convective coefficient,and efficiency,were systematically evaluated.The system achieved a maximum outlet water temperature of 67℃and a peak thermal efficiency of 91.07%at the highest flow rate.The uncertainty analysis confirmed reliable measurements within±3.45%.The monthly energy savings were estimated at 178.35 kWh,accompanied by a reduction in CO_(2)emissions of up to 187.26 kg,yielding a short payback period of 1.06 years.These results demonstrate the feasibility of spiral-coil heat exchangers as cost-effective and eco-friendly alternatives to conventional electric water heaters.The proposed approach not only enhances the overall energy utilization but also contributes to energy conservation and climate mitigation objectives.展开更多
[Objectives]This study was conducted to improve the seed production efficiency of water-saving and drought-resistant hybrid millet in production.[Methods]A high-efficiency seed production technology for water-saving a...[Objectives]This study was conducted to improve the seed production efficiency of water-saving and drought-resistant hybrid millet in production.[Methods]A high-efficiency seed production technology for water-saving and drought-resistant hybrid millet varieties was developed by integrating aspects such as parental line sources,botanical characteristics,biological traits,seed production yield structure,key technical points of seed production,and suitable planting regions.[Results]Under standardized pre-sowing preparation and field management,both parents are simultaneously sown around May 20 with a planting row ratio of 2:6(female:male),a row spacing of 20 cm and plant spacing of 10 cm for the female parent,and a row spacing of 35 cm and plant spacing of 15 cm for the male parent.Both parents are fertilized simultaneously with 375 kg/hm^(2) of urea at the booting stage combined with intertillage or rainfall,and 225 kg/hm^(2) of urea at the grain-filling stage combined with irrigation.Strict hybrid removal,proper pollination and timely harvesting can significantly increase the yield of seed production.[Conclusions]This technology can be fully applied to large-scale seed production of water-saving and drought-resistant hybrid millet,providing seed supply support for cultivation in arid and semi-arid regions.It helps alleviate issues such as excessive groundwater extraction and water scarcity while enhancing planting efficiency,increasing yield,and boosting increase of farmers income.展开更多
Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements whe...Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements when working in complex terrains such as field stubble,waterlogged silt,and loose/firm terrain.These differentiated dynamics prevent cooperation between ETs and operating implements under independent control,resulting in poor quality operations and low energy efficiency.We propose a control mechanism for ETs and implements to achieve full life cycle management of collaborative control tasks,instantaneous intertask interaction,and a multitask synchronization mechanism.To address the internal redundant communication problems caused by traditional distributed microcontrol units,we break through the underlying technology of unit data processing and interaction and develop an integrated high-performance controller structure with high processing capacity and high-and low-speed communication interfaces.On the basis of hierarchical stepwise control theory,a hierarchical real-time operating system is designed.This system realizes a preemptive kernel response of computational tasks and competitive-collaborative synchronization among tasks;overcomes the low-latency response of collaborative control tasks,instantaneous information interaction,and multitask synchronization problems;and provides system-level support for deep collaborative operation control of units.To demonstrate and validate the proposed collaborative control mechanism,a plowing collaborative operation management strategy is designed and deployed.The experimental results show that the communication delay of collaborative tasks is as low as 83μs,the solution time of complex collaborative equations is as low as 46 ms,the mechanical efficiency of the ET is increased by 9.07%,the efficiency of the drive motor is increased by 9.72%,the stability of the operation speed is increased by 106.25%,and the stability of the plowing depth reaches 94.98%.Our work meets the hardware and software requirements for realizing complex collaborative control of ET units and improves the operational quality and operational energy efficiency in real vehicle demonstrations.展开更多
The advancement of sophisticated smart windows exhibiting superior thermoregulation capabilities in both solar spectrum and long-wave infrared range maintains a prominent objective for researchers in this field.In thi...The advancement of sophisticated smart windows exhibiting superior thermoregulation capabilities in both solar spectrum and long-wave infrared range maintains a prominent objective for researchers in this field.In this study,a Janus window is proposed and prepared based on polymer-stabilized liquid-crystal films/thermochromic materials.It can achieve switchable front long-wave infrared emissivity(ε_(Front))and solar modulation ability(ΔT_(sol))through dynamic flipping,making it suitable for different seasonal energy-saving requirements.Outdoor experiments show that under daytime illumination,the indoor temperature decreases by 8℃,and the nighttime temperature drops by 5℃.MATLAB simulation calculations indicate that the daytime cooling power is 93 W m^(-2),while the nighttime cooling power reaches 142 W m^(-2).Interestingly,by modifying the conductive layer,it can effectively shield electromagnetic radiation(within the X-band frequency range(8.2-12.4)GHz).Energy simulation reveals the substantial superiority of this device in energy savings compared with single-layer polymer-stabilized liquid crystal,poly(N-isopropyl acrylamide),and normal glass when applied in different climate zones.This research presents a compelling opportunity for the development of sophisticated smart windows characterized by exceptional thermoregulation capabilities.展开更多
Terahertz(THz)and millimeter Wave(mmWave)have been considered as potential frequency bands for 6G cellular systems to meet the need of ultra-high data rates.However,indoor communications could be blocked in THz/mmW ce...Terahertz(THz)and millimeter Wave(mmWave)have been considered as potential frequency bands for 6G cellular systems to meet the need of ultra-high data rates.However,indoor communications could be blocked in THz/mmW cellular systems due to the high free-space propagation loss.Deploying a large number of small base stations indoors has been considered as a promising solution for solving indoor coverage problems.However,base station dense deployment leads to a significant increase in system energy consumption.In this paper,we develop a novel ultra-e˙icient energy-saving mechanism with the aim of reducing energy consumption in 6G distributed indoor base station scenarios.Unlike the existing relevant protocol framework of 3GPP,which operates the cellular system based on constant system signaling messages(including cell ID,cell reselection information,etc.),the proposed mechanism eliminates the need for system messages.The intuition comes from the observation that the probability of having no users within the coverage area of an indoor base station is high,hence continuously sending system messages to guarantee the quality of service is unnecessary in indoor scenarios.Specifically,we design a dedicated beacon signal to detect whether there are users in the coverage area of the base station and switch offthe main communication module when there are no active users for energy saving.The beacon frame structure is carefully designed based on the existing 3GPP specifications with minimal protocol modifications,and the protocol parameters involved are optimized.Simulation results show that the proposed mechanism can reduce the system energy from the order of tens of watts to the order of hundreds of milliwatts.Compared to traditional energy-saving schemes,the proposed mechanism achieves an average energy-saving gain of 58%,with a peak energy-saving gain of 90%.展开更多
This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic...This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic numerical simulations conducted on two real buildings located near Florence,Italy,and modeled in 130 different European locations,with a particular focus on the Mediterranean climate,it was possible to quantify the energy benefits derived from the application of green roofs on existing structures.The results show that,while the effect on heating is limited,with an average reduction in energy demand of only a few percentage points,the impact on cooling is significantly more pronounced,with average savings of 20%in non-renewable primary energy,particularly in Mediterranean climates with high CDD(cooling degree days)values.The study confirms that green roofs can be an effective solution to improve the energy efficiency of existing buildings with flat roofs in the Mediterranean climate,in line with European goals for reducing CO₂emissions and promoting renewable energy.展开更多
BACKGROUND Conventional reusable endoscopes have high disinfection costs because of their large size.In this study,we compared the effectiveness,safety,and operation performance of the portable disposable large-channe...BACKGROUND Conventional reusable endoscopes have high disinfection costs because of their large size.In this study,we compared the effectiveness,safety,and operation performance of the portable disposable large-channel endoscope that we developed with those of a conventional gastroscope in endoscopic submucosal dissection(ESD).AIM To compare two gastroscopes in ESD for effectiveness and safety.METHODS Ten Bama pigs were subjected to gastroscopy and ESD after general anesthesia.The experiment was completed by four experienced endoscopists.First,two endoscopists randomly selected the portable disposable large-channel or conventional gastroscope to complete gastroscopy procedures.The other two endoscopists assessed the quality of endoscopic images.After endoscopy,all of the endoscopists randomly used the portable disposable large-channel endoscope or the conventional gastroscope for ESD.Endoscopic operation performance,submucosal dissection time,total procedure time,total submucosal injection volume,specimen size,success rate of en bloc resection,muscular injury rate,and complications were compared between the endoscopes.RESULTS No significant differences in gastroscopy duration or in the integrity,sharpness,saturation,and brightness of the gastroscopic images were observed between the gastroscopes.For ESD,no significant differences in endoscopic operation performance,incision time,submucosal dissection time,total procedure time,total submucosal injection volume,specimen size,or success rate of en bloc resection were observed between the gastroscopes.Neither gastroscope caused muscular injury or treatment-related complica-tions.CONCLUSION The portable disposable large-channel endoscope can be used safely and effectively for gastroscopy and treatment.展开更多
Hi,everyone!I started loving economics and money when I was only seven.When I was nine,I tried managing money for the fi rst time.I learned a lot from itmaybe even more than I learn in school!It all began after I read...Hi,everyone!I started loving economics and money when I was only seven.When I was nine,I tried managing money for the fi rst time.I learned a lot from itmaybe even more than I learn in school!It all began after I read a book about how kids can succeed with money.I felt excited and asked my mom for some money to start.She gave me 5,000 yuan.I spent a lot of time learning online about investing and saving.One day,I found something called online financial management,and I wanted to try it.展开更多
SHANGHAI is blazing a new development track powered by dual engines:one is intelligent manufacturing empowered by cutting-edge technologies,and the other is green development driven by lowcarbon and energy-saving solu...SHANGHAI is blazing a new development track powered by dual engines:one is intelligent manufacturing empowered by cutting-edge technologies,and the other is green development driven by lowcarbon and energy-saving solutions.On September 10,China Today visited two enterprises in Shanghai–Shanghai Schneider Electric Industrial Control Co.,Ltd.and Huaqin Technology Co.,Ltd.–to observe firsthand how global investment and local innovation are jointly shaping Shanghai’s future of high-quality development.展开更多
文摘Many people like to shop at a supermarket.Supermarkets are very convenient.They are open long hours,every day of the week.Everything is easy to find in a supermarket.It's always in the same place.Supermarkets often have sales.These can help you save money.
文摘好题精选阅读下面短文,从每题所给的A、B、C、D四个选项中选出最佳选项。Born during my parents'sea voyage(航行)around the world,I always wanted to make the trip myself.At age 8,I began saving and sailing to 1 that dream.My parents weren't excited about the idea,but after talking to them about it,they became 2.
文摘As an indispensable part of modern buildings,centralized central air conditioning systems play an important role in maintaining the comfort and air quality of the indoor environment.However,with the increasing energy consumption,how to improve the energy efficiency ratio of air conditioning systems and reduce energy consumption has become an important issue in research and practice.The purpose of this paper is to discuss the impact of humidity control strategies on energy saving in centralized central air conditioning systems,with a view to providing a theoretical basis and practical guidance for realizing building energy efficiency.
基金Supported by National Natural Science Foundation of China(Grant No.52075358).
文摘Load-sensing systems use a centralized power source for energy supply and multiway valves for flow distribution and suffer from excessive throttling losses and low energy efficiency.Pump-controlled systems adopt volumetric control methods to eliminate throttling losses.However,pump-controlled multi-actuator systems require excessive installed power.To address these issues,by combining the respective advantages of valve-and pump-controlled technologies,an open-closed circuit integrated pump-valve collaborative drive multi-actuator system consisting of pump-and valve-controlled units is proposed.The pump-controlled units manage the individual actuator motions,whereas the valve-controlled unit enhances the driving power of the pump-controlled units.In addition,to optimize the operation characteristics and energy consumption,a four-quadrant control strategy and an ultralow-pressure loss control strategy were proposed.Several experiments were conducted to evaluate the working performance of the proposed system and the load-sensing system under different working conditions.Experimental results demonstrated that the proposed system exhibited satisfactory velocity control characteristics.Compared with the traditional load-sensing system,the proposed system reduced throttling losses by 90.4−94.4%and energy consumption by 45.9−50.0%.Additionally,only 22.8%of the total energy consumption was attributed to the pump-controlled units,with the remainder provided by the valve-controlled unit.Compared with the traditional pump-controlled multi-actuator system,the proposed system achieved a 29.4%reduction in installed power,thereby lowering the system installed power and costs.This paper presents an electrohydraulic multi-actuator drive method that combines high energy efficiency and high power density and is suitable for electric construction machinery and other heavy equipment with multiple actuators.
文摘Jinmao Tex(short for Chongqing Jinmao Textile Accessories Co.,Ltd.),founded in 1960,is the largest manufacturer of ring traveller and steel ring in China,and its ring traveller delivery tops in China market for more than 30 consecutive years.In recent years,in order to serve the transformation and upgrading of the textile industry,Jinmao Tex invested"China Ring Traveller and Steel Ring R&D center",focused on the technological innovation of key textile accessories,developed high-performance and long-life textile accessories to assist textile mills save energy,reduce consumption,improve quality and increase efficiency.Jinmao Tex has now become a“steel ring+ring traveller”solution provider for high-speed spinning and differential fiber spinning.
文摘Heating,ventilation,and air conditioning(HVAC)systems contribute substantially to global energy consumption,while rejecting significant amounts of low-grade heat into the environment.This paper presents a nonintrusive spiral-coil heat exchanger designed to recover waste heat from the outdoor condenser of a split-type air conditioner.The system operates externally without altering the existing HVAC configuration,thereby rendering it suitable for retrofitting.Water was circulated as the working fluid at flow rates of 0.028–0.052 kg/s to assess thermal performance.Performance indicators,including the outlet water temperature,heat transfer rate,convective coefficient,and efficiency,were systematically evaluated.The system achieved a maximum outlet water temperature of 67℃and a peak thermal efficiency of 91.07%at the highest flow rate.The uncertainty analysis confirmed reliable measurements within±3.45%.The monthly energy savings were estimated at 178.35 kWh,accompanied by a reduction in CO_(2)emissions of up to 187.26 kg,yielding a short payback period of 1.06 years.These results demonstrate the feasibility of spiral-coil heat exchangers as cost-effective and eco-friendly alternatives to conventional electric water heaters.The proposed approach not only enhances the overall energy utilization but also contributes to energy conservation and climate mitigation objectives.
基金Supported by National Modern Agricultural Industry Technology System(CARS-06-14.5-A7)Hebei Provincial Agricultural Science and Technology Achievement Transformation Fund Project("Zhangzagu 19"Pilot Test and Demonstration).
文摘[Objectives]This study was conducted to improve the seed production efficiency of water-saving and drought-resistant hybrid millet in production.[Methods]A high-efficiency seed production technology for water-saving and drought-resistant hybrid millet varieties was developed by integrating aspects such as parental line sources,botanical characteristics,biological traits,seed production yield structure,key technical points of seed production,and suitable planting regions.[Results]Under standardized pre-sowing preparation and field management,both parents are simultaneously sown around May 20 with a planting row ratio of 2:6(female:male),a row spacing of 20 cm and plant spacing of 10 cm for the female parent,and a row spacing of 35 cm and plant spacing of 15 cm for the male parent.Both parents are fertilized simultaneously with 375 kg/hm^(2) of urea at the booting stage combined with intertillage or rainfall,and 225 kg/hm^(2) of urea at the grain-filling stage combined with irrigation.Strict hybrid removal,proper pollination and timely harvesting can significantly increase the yield of seed production.[Conclusions]This technology can be fully applied to large-scale seed production of water-saving and drought-resistant hybrid millet,providing seed supply support for cultivation in arid and semi-arid regions.It helps alleviate issues such as excessive groundwater extraction and water scarcity while enhancing planting efficiency,increasing yield,and boosting increase of farmers income.
基金supported by the National Key Research and Development Plan of China(2022YFD2001202)the National Natural Science Foundation of China(32301719 and 52272444)the 2115 Talent Development Program of China Agricultural University.
文摘Electric tractors(ETs)with mounted implements form operating units.There are significant differences in parameters such as shape,firmness,and moisture content of the soil in contact with the tractor and implements when working in complex terrains such as field stubble,waterlogged silt,and loose/firm terrain.These differentiated dynamics prevent cooperation between ETs and operating implements under independent control,resulting in poor quality operations and low energy efficiency.We propose a control mechanism for ETs and implements to achieve full life cycle management of collaborative control tasks,instantaneous intertask interaction,and a multitask synchronization mechanism.To address the internal redundant communication problems caused by traditional distributed microcontrol units,we break through the underlying technology of unit data processing and interaction and develop an integrated high-performance controller structure with high processing capacity and high-and low-speed communication interfaces.On the basis of hierarchical stepwise control theory,a hierarchical real-time operating system is designed.This system realizes a preemptive kernel response of computational tasks and competitive-collaborative synchronization among tasks;overcomes the low-latency response of collaborative control tasks,instantaneous information interaction,and multitask synchronization problems;and provides system-level support for deep collaborative operation control of units.To demonstrate and validate the proposed collaborative control mechanism,a plowing collaborative operation management strategy is designed and deployed.The experimental results show that the communication delay of collaborative tasks is as low as 83μs,the solution time of complex collaborative equations is as low as 46 ms,the mechanical efficiency of the ET is increased by 9.07%,the efficiency of the drive motor is increased by 9.72%,the stability of the operation speed is increased by 106.25%,and the stability of the plowing depth reaches 94.98%.Our work meets the hardware and software requirements for realizing complex collaborative control of ET units and improves the operational quality and operational energy efficiency in real vehicle demonstrations.
基金supported by the National Natural Science Foundation of China(52372279,52103071,52203322,52473289,52303220)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities in China,FRF-IDRY-GD22-001)。
文摘The advancement of sophisticated smart windows exhibiting superior thermoregulation capabilities in both solar spectrum and long-wave infrared range maintains a prominent objective for researchers in this field.In this study,a Janus window is proposed and prepared based on polymer-stabilized liquid-crystal films/thermochromic materials.It can achieve switchable front long-wave infrared emissivity(ε_(Front))and solar modulation ability(ΔT_(sol))through dynamic flipping,making it suitable for different seasonal energy-saving requirements.Outdoor experiments show that under daytime illumination,the indoor temperature decreases by 8℃,and the nighttime temperature drops by 5℃.MATLAB simulation calculations indicate that the daytime cooling power is 93 W m^(-2),while the nighttime cooling power reaches 142 W m^(-2).Interestingly,by modifying the conductive layer,it can effectively shield electromagnetic radiation(within the X-band frequency range(8.2-12.4)GHz).Energy simulation reveals the substantial superiority of this device in energy savings compared with single-layer polymer-stabilized liquid crystal,poly(N-isopropyl acrylamide),and normal glass when applied in different climate zones.This research presents a compelling opportunity for the development of sophisticated smart windows characterized by exceptional thermoregulation capabilities.
基金supported by the National Natural Science Foundation of China under Grant No.62201121the Fundamental Fundamental Research Funds for Central Universities under Grant No.ZYGX2024XJ070。
文摘Terahertz(THz)and millimeter Wave(mmWave)have been considered as potential frequency bands for 6G cellular systems to meet the need of ultra-high data rates.However,indoor communications could be blocked in THz/mmW cellular systems due to the high free-space propagation loss.Deploying a large number of small base stations indoors has been considered as a promising solution for solving indoor coverage problems.However,base station dense deployment leads to a significant increase in system energy consumption.In this paper,we develop a novel ultra-e˙icient energy-saving mechanism with the aim of reducing energy consumption in 6G distributed indoor base station scenarios.Unlike the existing relevant protocol framework of 3GPP,which operates the cellular system based on constant system signaling messages(including cell ID,cell reselection information,etc.),the proposed mechanism eliminates the need for system messages.The intuition comes from the observation that the probability of having no users within the coverage area of an indoor base station is high,hence continuously sending system messages to guarantee the quality of service is unnecessary in indoor scenarios.Specifically,we design a dedicated beacon signal to detect whether there are users in the coverage area of the base station and switch offthe main communication module when there are no active users for energy saving.The beacon frame structure is carefully designed based on the existing 3GPP specifications with minimal protocol modifications,and the protocol parameters involved are optimized.Simulation results show that the proposed mechanism can reduce the system energy from the order of tens of watts to the order of hundreds of milliwatts.Compared to traditional energy-saving schemes,the proposed mechanism achieves an average energy-saving gain of 58%,with a peak energy-saving gain of 90%.
文摘This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic numerical simulations conducted on two real buildings located near Florence,Italy,and modeled in 130 different European locations,with a particular focus on the Mediterranean climate,it was possible to quantify the energy benefits derived from the application of green roofs on existing structures.The results show that,while the effect on heating is limited,with an average reduction in energy demand of only a few percentage points,the impact on cooling is significantly more pronounced,with average savings of 20%in non-renewable primary energy,particularly in Mediterranean climates with high CDD(cooling degree days)values.The study confirms that green roofs can be an effective solution to improve the energy efficiency of existing buildings with flat roofs in the Mediterranean climate,in line with European goals for reducing CO₂emissions and promoting renewable energy.
文摘BACKGROUND Conventional reusable endoscopes have high disinfection costs because of their large size.In this study,we compared the effectiveness,safety,and operation performance of the portable disposable large-channel endoscope that we developed with those of a conventional gastroscope in endoscopic submucosal dissection(ESD).AIM To compare two gastroscopes in ESD for effectiveness and safety.METHODS Ten Bama pigs were subjected to gastroscopy and ESD after general anesthesia.The experiment was completed by four experienced endoscopists.First,two endoscopists randomly selected the portable disposable large-channel or conventional gastroscope to complete gastroscopy procedures.The other two endoscopists assessed the quality of endoscopic images.After endoscopy,all of the endoscopists randomly used the portable disposable large-channel endoscope or the conventional gastroscope for ESD.Endoscopic operation performance,submucosal dissection time,total procedure time,total submucosal injection volume,specimen size,success rate of en bloc resection,muscular injury rate,and complications were compared between the endoscopes.RESULTS No significant differences in gastroscopy duration or in the integrity,sharpness,saturation,and brightness of the gastroscopic images were observed between the gastroscopes.For ESD,no significant differences in endoscopic operation performance,incision time,submucosal dissection time,total procedure time,total submucosal injection volume,specimen size,or success rate of en bloc resection were observed between the gastroscopes.Neither gastroscope caused muscular injury or treatment-related complica-tions.CONCLUSION The portable disposable large-channel endoscope can be used safely and effectively for gastroscopy and treatment.
文摘Hi,everyone!I started loving economics and money when I was only seven.When I was nine,I tried managing money for the fi rst time.I learned a lot from itmaybe even more than I learn in school!It all began after I read a book about how kids can succeed with money.I felt excited and asked my mom for some money to start.She gave me 5,000 yuan.I spent a lot of time learning online about investing and saving.One day,I found something called online financial management,and I wanted to try it.
文摘SHANGHAI is blazing a new development track powered by dual engines:one is intelligent manufacturing empowered by cutting-edge technologies,and the other is green development driven by lowcarbon and energy-saving solutions.On September 10,China Today visited two enterprises in Shanghai–Shanghai Schneider Electric Industrial Control Co.,Ltd.and Huaqin Technology Co.,Ltd.–to observe firsthand how global investment and local innovation are jointly shaping Shanghai’s future of high-quality development.
