Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal condu...Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.展开更多
In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-p...In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-propeller is studied by analyzing the complex force situation during ship navigation and building a MATLAB/Simulink simulation platform based on multi-environmental resistance,propeller efficiency,main engine power,fuel consumption,fuel consumption rate and EEOI calculation module.Considering the environmental factors of wind,wave and ice,the route is divided into sections,the calculation of main engine power,main engine fuel consumption and EEOI for each section is completed,and the speed design is optimized based on the simulation model for each section.Under the requirements of the voyage plan,the optimization results show that the energy efficiency operation index of the whole route is reduced by 3.114%and the fuel consumption is reduced by 9.17 t.展开更多
The CO2 emission reduction policy of the International Maritime Organization(IMO)recommends that the operation of ships,managed by maritime transport companies,should be energy-efficient.An evaluation method that can ...The CO2 emission reduction policy of the International Maritime Organization(IMO)recommends that the operation of ships,managed by maritime transport companies,should be energy-efficient.An evaluation method that can determine how successfully a ship implements the energy efficiency plan is proposed in this study.To develop this method,the measures required for energy-efficient ship operations according to the Ship Energy Efficiency Management Plan(SEEMP)operational guidelines were selected.The weights of the selected measures,which indicate how they contribute to the energy-efficient operation of a ship,were derived using a survey based on the analytic hierarchy process(AHP)method.Consequently,using these measures and their weights,a new evaluation method was proposed.This evaluation method was applied to shipping companies in South Korea,and their ship operation energy efficiency indices were derived and compared.This evaluation method will be useful to the government and shipping companies in assessing the energy efficiency of ship operations.展开更多
A new approach for prediction of face advance rete (FAR) prior to mining operation and determination of the operation efficiency after mining operation in retreat longwall mining panel is presented based upon the conc...A new approach for prediction of face advance rete (FAR) prior to mining operation and determination of the operation efficiency after mining operation in retreat longwall mining panel is presented based upon the concepts of rock engineering system (RES). For this purpose, six longwall panels considered in Parvadeh-I coal mine. Seven major effective parameters on FAR was selected including coal mine roof rating, gas propagation, safety factor of longwall face, ratio of joint spacing to cutting depth at longwall face, longwall face inclination, panel width, floor rock mass rating. To performance evaluation of the presented model, the relationship between the average vulnerability indexes of advance operation with FAR was determined in considered panels with coefficient of determination (R2) equal to 0.884 that indicate relatively acceptable correlation and compatibility. Investigations of the research indicated that it is possible to determine the actual operation efficiency under fair conditions by a RES-based model. The inevitable reduction of FAR for each longwall panel was determined by presented model that the difference amount between the maximum possible practical face advance rate (FARmpp) and recorded actual face advance rate (FARa) indicate the operation efficiency. Applied approach in this paper can be used to prediction of FAR in retreat longwall mining panel for same conditions that can have many benefits, including better and more accurate planning for the sales market and mine operation. Also, presented method in this paper can be applied as a useful tool to determination of actual operation efficiency for other sections and extraction methods in coal mines.展开更多
The efficiency of any energy system can be charaterised by the relevant efficiency components in terms of performance, operation, equipment and technology(POET). The overall energy efficiency of the system can be opti...The efficiency of any energy system can be charaterised by the relevant efficiency components in terms of performance, operation, equipment and technology(POET). The overall energy efficiency of the system can be optimised by studying the POET energy efficiency components. For an existing energy system, the improvement of operation efficiency will usually be a quick win for energy efficiency. Therefore, operation efficiency improvement will be the main purpose of this paper. General procedures to establish operation efficiency optimisation models are presented. Model predictive control, a popular technique in modern control theory, is applied to solve the obtained energy models. From the case studies in water pumping systems, model predictive control will have a prosperous application in more energy efficiency problems.展开更多
We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angl...We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angles, operational efficiency of bunching operations with road network density, and average forwarding distances with operation site areas. Subsequently, we analyzed the effects of aggregating forests, establishing forest road networks, and mechanization on operational efficiency and costs. Six ha proved to be an appropriate operation site area with minimum operation expenses. The operation site areas of the forest owners＇ cooperative in this region aggregated approximately 6 ha and the cooperative conducted forestry operations on aggregated sites. Therefore, 6 ha would be an appropriate operation site area in this region. Regarding road network density, higher-density road networks increased operational expenses due to the higher direct operational expenses of strip road establishment. Therefore, road network density should be reduced to approximately 200 m.展开更多
From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency...From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency and its influencing factors,in order to improve the operational efficiency of agricultural insurance agency,better supply agricultural insurance and achieve the policy effect of agricultural insurance.The results of this paper are as follows:( i) Either comprehensive operational efficiency or scale efficiency of Chinese-funded agency is higher than that of foreign-funded agency,but its pure technical efficiency is lower than that of foreign-funded agency,indicating that the managerial decision ability of Chinese-funded agency is weaker than that of foreign-funded agency,and needs to be improved;( ii) The operational efficiency of professional agricultural insurance agency is higher than that of comprehensive agricultural insurance agency,and the agricultural insurance agency is greatly affected by environmental factors;( iii) The operating time of agricultural insurance agency is proportional to its operational efficiency;( iv) The quality of employees is positively correlated with the capital and cost input difference,but negatively correlated with the difference in the number of employees. Therefore,it is necessary to pay attention to the improvement of employees' working efficiency while laying emphasis on employees' quality.展开更多
Listed companies of the swine industry,as an important form of agricultural industrialized operation,are typical representatives of large-scale production and the level of their operation efficiency exerts a direct in...Listed companies of the swine industry,as an important form of agricultural industrialized operation,are typical representatives of large-scale production and the level of their operation efficiency exerts a direct influence on the healthy development of the swine industry.Using the DEA-based Malmquist method,this paper made a static and dynamic evaluation of the operation efficiency of 16 listed companies in China's swine industry in 2010-2014.It obtained following results:(i)The overall efficiency of listed companies of China's swine industry remained at high level and the development trend was excellent.(ii)Different types of enterprises had difference in the overall efficiency,pure technical efficiency and scale efficiency.In general,pig feed processing companies had the best performance,followed by slaughtering and deep processing companies,and swine breeding companies were the worst.(iii)The total factor productivity characterized by the Malmquist index declined year by year in 2010-2013 and was improved in 2014,mainly due to technological progress.(iv)The total asset turnover ratio,equity concentration,and R&D management level had a significantly positive impact on the operation efficiency of listed companies in the swine industry,while the human capital had a significantly negative impact.展开更多
Objective: To measure the hospital operation efficiency, study the correlation between average length of stay and hospital operation efficiency, analyze the importance of shortening average length of stay to the impro...Objective: To measure the hospital operation efficiency, study the correlation between average length of stay and hospital operation efficiency, analyze the importance of shortening average length of stay to the improvement of the hospital operation efficiency and put forward relevant policy suggestion. Methods: Based on China provincial panel data from 2003 to 2012, the hospital operation efficiencies are calculated using Super Efficiency Data Envelopment Analysis model, and the correlation between average length of stay and hospital operation efficiency is tested using Spearman rank correlation coefficient test. Results: From 2003 to 2012, the average of national hospital operation efficiency was increasing slowly and the hospital operations were inefficient in most of the areas. The national hospital operation efficiency is negatively correlated to the average length of stay. Conclusion: Measures should be taken to set average length of stay in a scientific and reasonable way, improve social and economic benefits based on the improvement of efficiency.展开更多
The data envelopment analysis （DEA） is used to evaluate operation efficiency of 17 listed companies in China aviation industry from 2006 to 2011, and make longitudinal analysis for the operation efficiency. In addit...The data envelopment analysis （DEA） is used to evaluate operation efficiency of 17 listed companies in China aviation industry from 2006 to 2011, and make longitudinal analysis for the operation efficiency. In addition, the reason of changing efficiency is dynamically evaluated by Malmquist productivity index. The empirical results show that average operation efficiency of 17 listed companies in China aviation industry is less than 1, which means that the operation activities of aviation industry exist diseconomies characteristic, technological progress efficiency is a major influenced factor展开更多
Shoot efficiency is one of the most important evaluation indexes of the operation efficiency of weapon system.In this paper,based on definitions of the probability and the expected number of missed attacking missiles,...Shoot efficiency is one of the most important evaluation indexes of the operation efficiency of weapon system.In this paper,based on definitions of the probability and the expected number of missed attacking missiles,the expected numbers of anti-missiles and attacking missiles hit by single anti-missile,fusillade mechanism of multi-missile is analyzed systematically.The weapon operation efficiency in various engagement patterns is also studied.The results show that double missiles fusillade is the most feasible manner for increasing the weapon operation efficiency.展开更多
Comparison method and vidco-tape recorders were used in case study for recording thc operation performances of two group operators. The time span was 7 months, from September 10 March. The performance of operations in...Comparison method and vidco-tape recorders were used in case study for recording thc operation performances of two group operators. The time span was 7 months, from September 10 March. The performance of operations in September was taken as references. The results of test survey and data analysis showed that the tree-felling operation efficiency was influenced by cold weather, properly decreased 18.5% in average.展开更多
This paper discusses two urgent problems that need to be solved in fully automatic operation(FAO)for urban rail transit.The first is the analysis of safety in FAO,while another is the analysis of efficiency in FAO.Fir...This paper discusses two urgent problems that need to be solved in fully automatic operation(FAO)for urban rail transit.The first is the analysis of safety in FAO,while another is the analysis of efficiency in FAO.Firstly,this paper establishes an operational safety evaluation index system from the perspective of operation for the unique or typical risk sources of the FAO system,and uses the analytic hierarchy process(AHP)to evaluate the indicators,analyzes various factors that affect the safe operation of FAO,and provides safety management recommendations for FAO lines operation to maintain the FAO system specifically.Secondly,taking the Yanfang Line as an example,this paper uses OpenTrack software to analyze the efficiency of FAO operation,and conducts simulation calculations for key links such as the mainline tracking interval,train entry and exit,and return limit interval.The fault impact surface of the FAO trains is simulated and discussed to verify whether FAO can meet the long-term operation requirements of Yanfang Line.Finally,this paper compares the simulation data of FAO on the Yanfang Line with manual operation(MO)to verify the advantages of FAO and guide the engineering construction of subsequent fully automated driving lines.展开更多
With the implementation of China’s reform and opening up policy and China’s successful accession to the World Trade Organization,more and more overseas financial institutions are participating in various Chinese ban...With the implementation of China’s reform and opening up policy and China’s successful accession to the World Trade Organization,more and more overseas financial institutions are participating in various Chinese banks,and the amount of investment is also expanding.Therefore,it is particularly important to study the impact of overseas financial institutions participating in the Chinese Banks on the operating efficiency of the China’s banking industry.Therefore,based on the previous literature research,this paper constructs six models to explore whether foreign financial institutions participate in shares and the impact of shareholding ratio on the operating efficiency of China’s banking industry.展开更多
In this paper, we conduct research on the logistics cost and enterprise operation efficiency with the influences on international trade. With the deepening of the reform of the market economic system in our country, a...In this paper, we conduct research on the logistics cost and enterprise operation efficiency with the influences on international trade. With the deepening of the reform of the market economic system in our country, and the advancement of the reform of state-owned enterprises and government function transformation, the company is out of the shackles of the planned economy as the main body of market competition, at the same time, government regulators and investors in a state-owned capital market, all kinds of financial intermediaries and the information intermediary organizations, as well as the associated with the interests of closely linked to the enterprise value creation main body, including business owners and operators have yet to establish a timely to adapt to the market economy system. With this guidance, we propose the novel international trade paradigm for the companies that will enhance the efficiency of the general management.展开更多
Objective: to explore the effect of nursing intervention in operating room on improving the cooperation efficiency of laparoscopic surgery. Methods: from April 2020 to April 2021, 100 cases of laparoscopic surgery pat...Objective: to explore the effect of nursing intervention in operating room on improving the cooperation efficiency of laparoscopic surgery. Methods: from April 2020 to April 2021, 100 cases of laparoscopic surgery patients in our hospital were randomly divided into two groups. The routine group was given routine nursing, while the intervention group was given nursing intervention in the operating room. The anxiety level, pain level, complication rate, exhaust time and hospitalization time before and after nursing were compared between the two groups. Results: after nursing, the anxiety and pain levels of the two groups were significantly improved, while the anxiety level of the intervention group was significantly lower than that of the conventional group, and the pain level of the intervention group was significantly lower than that of the conventional group (P < 0.05). The incidence of complications in the intervention group was lower than that in the conventional group (P < 0.05). The exhaust time and hospitalization time of the intervention group were shorter than those of the routine group (P < 0.05). Conclusion: the effect of nursing intervention in operating room for patients undergoing laparoscopic surgery is definite, which can reduce complications, accelerate postoperative recovery of patients and recovery of gastrointestinal function, and reduce anxiety and pain of patients. It is worthy of promotion.展开更多
Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration eff...Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.展开更多
We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a c...We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a container. Such a forwarder can shorten the loading and untoading times and improve operational efficiency. We examined two operation systems with an arm roll forwarder and a forwarder. In the first system the loading was done with a grapple-loader. In the second system the loading was done with a processor. The loading times of an arm roll forwarder were significantly tess than those of a forwarder. Because the optimal cycle times （excluding the waiting times for an arm roll for- warder） were significantly reduced, the costs of using an arm roll for- warder are lower, although the loading capacity was small and the hourly operation cost was high. The maximum operational efficiencies varied depending on forwarding distances. The second operation system with an arm roll forwarder exhibited the best operational efficiency within a 1,580-m forwarding distance, and beyond that distance it exhibited the highest operational efficiency when a forwarder was used. Similarly, the cost of operation of the system with an arm roll forwarder was the lowest within a 1,130-m forwarding distance, and beyond that distance the cost was the lowest when using the forwarder. Therefore, the arm roll for- warder is effective within a certain forwarding distance.展开更多
Enhancing the efficiency of Rankine cycles is crucial for improving the performance of thermal power plants,as it directly impacts operational costs and emissions in light of energy transition goals.This study sets it...Enhancing the efficiency of Rankine cycles is crucial for improving the performance of thermal power plants,as it directly impacts operational costs and emissions in light of energy transition goals.This study sets itself apart from existing research by applying a novel optimization technique to a basic ideal Rankine cycle,focusing on a specific power plant that has not been previously analyzed.Currently,this cycle operates at 41%efficiency and a steam quality of 76%,constrained by fixed operational parameters.The primary objectives are to increase thermal efficiency beyond 46%and raise steam quality above 85%,while adhering to operational limits:a boiler pressure not exceeding 15 MPa,condenser pressure not dropping below 10 kPa,and turbine temperature not surpassing 500℃.This study utilizes numerical simulations to model the effects of varying boiler pressure(Pb)and condenser pressure(Pc)within the ranges of 12MPa<Pb<15 MPa and 5 kPa<Pc<10 kPa.By systematically adjusting these parameters,the proposed aimto identify optimal conditions that maximize efficiency and performance within specified constraints.The findings will provide valuable insights for power plant operators seeking to optimize performance under real-world conditions,contributing to more efficient and sustainable power generation.展开更多
The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium he...The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.展开更多
基金financially supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(No.2016R1A3B1908249,RS202400407199).
文摘Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.
文摘In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-propeller is studied by analyzing the complex force situation during ship navigation and building a MATLAB/Simulink simulation platform based on multi-environmental resistance,propeller efficiency,main engine power,fuel consumption,fuel consumption rate and EEOI calculation module.Considering the environmental factors of wind,wave and ice,the route is divided into sections,the calculation of main engine power,main engine fuel consumption and EEOI for each section is completed,and the speed design is optimized based on the simulation model for each section.Under the requirements of the voyage plan,the optimization results show that the energy efficiency operation index of the whole route is reduced by 3.114%and the fuel consumption is reduced by 9.17 t.
基金support from the project titled "Development of Ship-handling and Passenger Evacuation Support System" funded by the Ministry of Oceans and Fisheries(South Korea-MOF)
文摘The CO2 emission reduction policy of the International Maritime Organization(IMO)recommends that the operation of ships,managed by maritime transport companies,should be energy-efficient.An evaluation method that can determine how successfully a ship implements the energy efficiency plan is proposed in this study.To develop this method,the measures required for energy-efficient ship operations according to the Ship Energy Efficiency Management Plan(SEEMP)operational guidelines were selected.The weights of the selected measures,which indicate how they contribute to the energy-efficient operation of a ship,were derived using a survey based on the analytic hierarchy process(AHP)method.Consequently,using these measures and their weights,a new evaluation method was proposed.This evaluation method was applied to shipping companies in South Korea,and their ship operation energy efficiency indices were derived and compared.This evaluation method will be useful to the government and shipping companies in assessing the energy efficiency of ship operations.
文摘A new approach for prediction of face advance rete (FAR) prior to mining operation and determination of the operation efficiency after mining operation in retreat longwall mining panel is presented based upon the concepts of rock engineering system (RES). For this purpose, six longwall panels considered in Parvadeh-I coal mine. Seven major effective parameters on FAR was selected including coal mine roof rating, gas propagation, safety factor of longwall face, ratio of joint spacing to cutting depth at longwall face, longwall face inclination, panel width, floor rock mass rating. To performance evaluation of the presented model, the relationship between the average vulnerability indexes of advance operation with FAR was determined in considered panels with coefficient of determination (R2) equal to 0.884 that indicate relatively acceptable correlation and compatibility. Investigations of the research indicated that it is possible to determine the actual operation efficiency under fair conditions by a RES-based model. The inevitable reduction of FAR for each longwall panel was determined by presented model that the difference amount between the maximum possible practical face advance rate (FARmpp) and recorded actual face advance rate (FARa) indicate the operation efficiency. Applied approach in this paper can be used to prediction of FAR in retreat longwall mining panel for same conditions that can have many benefits, including better and more accurate planning for the sales market and mine operation. Also, presented method in this paper can be applied as a useful tool to determination of actual operation efficiency for other sections and extraction methods in coal mines.
基金supported by National Research Foundation of South Africa(UID85783)the National Hub for Energy Efficiency and Demand Side Management and Exxaro
文摘The efficiency of any energy system can be charaterised by the relevant efficiency components in terms of performance, operation, equipment and technology(POET). The overall energy efficiency of the system can be optimised by studying the POET energy efficiency components. For an existing energy system, the improvement of operation efficiency will usually be a quick win for energy efficiency. Therefore, operation efficiency improvement will be the main purpose of this paper. General procedures to establish operation efficiency optimisation models are presented. Model predictive control, a popular technique in modern control theory, is applied to solve the obtained energy models. From the case studies in water pumping systems, model predictive control will have a prosperous application in more energy efficiency problems.
文摘We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with average slope angles, operational efficiency of bunching operations with road network density, and average forwarding distances with operation site areas. Subsequently, we analyzed the effects of aggregating forests, establishing forest road networks, and mechanization on operational efficiency and costs. Six ha proved to be an appropriate operation site area with minimum operation expenses. The operation site areas of the forest owners＇ cooperative in this region aggregated approximately 6 ha and the cooperative conducted forestry operations on aggregated sites. Therefore, 6 ha would be an appropriate operation site area in this region. Regarding road network density, higher-density road networks increased operational expenses due to the higher direct operational expenses of strip road establishment. Therefore, road network density should be reduced to approximately 200 m.
文摘From the perspective of agricultural insurance agency,this paper focuses on the study of operational efficiency of agricultural insurance agency,and analyzes the operational efficiency of agricultural insurance agency and its influencing factors,in order to improve the operational efficiency of agricultural insurance agency,better supply agricultural insurance and achieve the policy effect of agricultural insurance.The results of this paper are as follows:( i) Either comprehensive operational efficiency or scale efficiency of Chinese-funded agency is higher than that of foreign-funded agency,but its pure technical efficiency is lower than that of foreign-funded agency,indicating that the managerial decision ability of Chinese-funded agency is weaker than that of foreign-funded agency,and needs to be improved;( ii) The operational efficiency of professional agricultural insurance agency is higher than that of comprehensive agricultural insurance agency,and the agricultural insurance agency is greatly affected by environmental factors;( iii) The operating time of agricultural insurance agency is proportional to its operational efficiency;( iv) The quality of employees is positively correlated with the capital and cost input difference,but negatively correlated with the difference in the number of employees. Therefore,it is necessary to pay attention to the improvement of employees' working efficiency while laying emphasis on employees' quality.
基金Supported by Young Scholar Project of Humanities and Social Science Foundation of Ministry of Education"Study on Stability Mechanism of Symbiosis Network of the Swine Industry"(15YJC630118)
文摘Listed companies of the swine industry,as an important form of agricultural industrialized operation,are typical representatives of large-scale production and the level of their operation efficiency exerts a direct influence on the healthy development of the swine industry.Using the DEA-based Malmquist method,this paper made a static and dynamic evaluation of the operation efficiency of 16 listed companies in China's swine industry in 2010-2014.It obtained following results:(i)The overall efficiency of listed companies of China's swine industry remained at high level and the development trend was excellent.(ii)Different types of enterprises had difference in the overall efficiency,pure technical efficiency and scale efficiency.In general,pig feed processing companies had the best performance,followed by slaughtering and deep processing companies,and swine breeding companies were the worst.(iii)The total factor productivity characterized by the Malmquist index declined year by year in 2010-2013 and was improved in 2014,mainly due to technological progress.(iv)The total asset turnover ratio,equity concentration,and R&D management level had a significantly positive impact on the operation efficiency of listed companies in the swine industry,while the human capital had a significantly negative impact.
文摘Objective: To measure the hospital operation efficiency, study the correlation between average length of stay and hospital operation efficiency, analyze the importance of shortening average length of stay to the improvement of the hospital operation efficiency and put forward relevant policy suggestion. Methods: Based on China provincial panel data from 2003 to 2012, the hospital operation efficiencies are calculated using Super Efficiency Data Envelopment Analysis model, and the correlation between average length of stay and hospital operation efficiency is tested using Spearman rank correlation coefficient test. Results: From 2003 to 2012, the average of national hospital operation efficiency was increasing slowly and the hospital operations were inefficient in most of the areas. The national hospital operation efficiency is negatively correlated to the average length of stay. Conclusion: Measures should be taken to set average length of stay in a scientific and reasonable way, improve social and economic benefits based on the improvement of efficiency.
基金supported by the Humanities and Social Science Foundation of the Chinese Ministry of Education under Grant No.09YJA630133
文摘The data envelopment analysis （DEA） is used to evaluate operation efficiency of 17 listed companies in China aviation industry from 2006 to 2011, and make longitudinal analysis for the operation efficiency. In addition, the reason of changing efficiency is dynamically evaluated by Malmquist productivity index. The empirical results show that average operation efficiency of 17 listed companies in China aviation industry is less than 1, which means that the operation activities of aviation industry exist diseconomies characteristic, technological progress efficiency is a major influenced factor
基金the National Science Foundation of China (70671105)
文摘Shoot efficiency is one of the most important evaluation indexes of the operation efficiency of weapon system.In this paper,based on definitions of the probability and the expected number of missed attacking missiles,the expected numbers of anti-missiles and attacking missiles hit by single anti-missile,fusillade mechanism of multi-missile is analyzed systematically.The weapon operation efficiency in various engagement patterns is also studied.The results show that double missiles fusillade is the most feasible manner for increasing the weapon operation efficiency.
文摘Comparison method and vidco-tape recorders were used in case study for recording thc operation performances of two group operators. The time span was 7 months, from September 10 March. The performance of operations in September was taken as references. The results of test survey and data analysis showed that the tree-felling operation efficiency was influenced by cold weather, properly decreased 18.5% in average.
文摘This paper discusses two urgent problems that need to be solved in fully automatic operation(FAO)for urban rail transit.The first is the analysis of safety in FAO,while another is the analysis of efficiency in FAO.Firstly,this paper establishes an operational safety evaluation index system from the perspective of operation for the unique or typical risk sources of the FAO system,and uses the analytic hierarchy process(AHP)to evaluate the indicators,analyzes various factors that affect the safe operation of FAO,and provides safety management recommendations for FAO lines operation to maintain the FAO system specifically.Secondly,taking the Yanfang Line as an example,this paper uses OpenTrack software to analyze the efficiency of FAO operation,and conducts simulation calculations for key links such as the mainline tracking interval,train entry and exit,and return limit interval.The fault impact surface of the FAO trains is simulated and discussed to verify whether FAO can meet the long-term operation requirements of Yanfang Line.Finally,this paper compares the simulation data of FAO on the Yanfang Line with manual operation(MO)to verify the advantages of FAO and guide the engineering construction of subsequent fully automated driving lines.
文摘With the implementation of China’s reform and opening up policy and China’s successful accession to the World Trade Organization,more and more overseas financial institutions are participating in various Chinese banks,and the amount of investment is also expanding.Therefore,it is particularly important to study the impact of overseas financial institutions participating in the Chinese Banks on the operating efficiency of the China’s banking industry.Therefore,based on the previous literature research,this paper constructs six models to explore whether foreign financial institutions participate in shares and the impact of shareholding ratio on the operating efficiency of China’s banking industry.
文摘In this paper, we conduct research on the logistics cost and enterprise operation efficiency with the influences on international trade. With the deepening of the reform of the market economic system in our country, and the advancement of the reform of state-owned enterprises and government function transformation, the company is out of the shackles of the planned economy as the main body of market competition, at the same time, government regulators and investors in a state-owned capital market, all kinds of financial intermediaries and the information intermediary organizations, as well as the associated with the interests of closely linked to the enterprise value creation main body, including business owners and operators have yet to establish a timely to adapt to the market economy system. With this guidance, we propose the novel international trade paradigm for the companies that will enhance the efficiency of the general management.
文摘Objective: to explore the effect of nursing intervention in operating room on improving the cooperation efficiency of laparoscopic surgery. Methods: from April 2020 to April 2021, 100 cases of laparoscopic surgery patients in our hospital were randomly divided into two groups. The routine group was given routine nursing, while the intervention group was given nursing intervention in the operating room. The anxiety level, pain level, complication rate, exhaust time and hospitalization time before and after nursing were compared between the two groups. Results: after nursing, the anxiety and pain levels of the two groups were significantly improved, while the anxiety level of the intervention group was significantly lower than that of the conventional group, and the pain level of the intervention group was significantly lower than that of the conventional group (P < 0.05). The incidence of complications in the intervention group was lower than that in the conventional group (P < 0.05). The exhaust time and hospitalization time of the intervention group were shorter than those of the routine group (P < 0.05). Conclusion: the effect of nursing intervention in operating room for patients undergoing laparoscopic surgery is definite, which can reduce complications, accelerate postoperative recovery of patients and recovery of gastrointestinal function, and reduce anxiety and pain of patients. It is worthy of promotion.
基金supported by the National Natural Science Foundation of China(No.92367107)。
文摘Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.
文摘We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a container. Such a forwarder can shorten the loading and untoading times and improve operational efficiency. We examined two operation systems with an arm roll forwarder and a forwarder. In the first system the loading was done with a grapple-loader. In the second system the loading was done with a processor. The loading times of an arm roll forwarder were significantly tess than those of a forwarder. Because the optimal cycle times （excluding the waiting times for an arm roll for- warder） were significantly reduced, the costs of using an arm roll for- warder are lower, although the loading capacity was small and the hourly operation cost was high. The maximum operational efficiencies varied depending on forwarding distances. The second operation system with an arm roll forwarder exhibited the best operational efficiency within a 1,580-m forwarding distance, and beyond that distance it exhibited the highest operational efficiency when a forwarder was used. Similarly, the cost of operation of the system with an arm roll forwarder was the lowest within a 1,130-m forwarding distance, and beyond that distance the cost was the lowest when using the forwarder. Therefore, the arm roll for- warder is effective within a certain forwarding distance.
文摘Enhancing the efficiency of Rankine cycles is crucial for improving the performance of thermal power plants,as it directly impacts operational costs and emissions in light of energy transition goals.This study sets itself apart from existing research by applying a novel optimization technique to a basic ideal Rankine cycle,focusing on a specific power plant that has not been previously analyzed.Currently,this cycle operates at 41%efficiency and a steam quality of 76%,constrained by fixed operational parameters.The primary objectives are to increase thermal efficiency beyond 46%and raise steam quality above 85%,while adhering to operational limits:a boiler pressure not exceeding 15 MPa,condenser pressure not dropping below 10 kPa,and turbine temperature not surpassing 500℃.This study utilizes numerical simulations to model the effects of varying boiler pressure(Pb)and condenser pressure(Pc)within the ranges of 12MPa<Pb<15 MPa and 5 kPa<Pc<10 kPa.By systematically adjusting these parameters,the proposed aimto identify optimal conditions that maximize efficiency and performance within specified constraints.The findings will provide valuable insights for power plant operators seeking to optimize performance under real-world conditions,contributing to more efficient and sustainable power generation.
基金supported by the Science,Technology,and Innovation Commission of Shenzhen Municipality(No.GJHZ20220913143204008)the Shccig-Qinling Program(No.SMYJY202300294C)+3 种基金National Natural Science Foundation of China(Nos.22261142666,52372225,52172237,22305191)the Shaanxi Science Fund for Distinguished Young Scholars(No.2022JC-21)the Research Fund of the State Key Laboratory of Solidification Processing(NPU)China(No.2021-QZ-02).
文摘The stability of perovskite solar cells(PSCs)is adversely affected by nonradiative recombination resulting from buried interface defects.Herein,we synthesize a polyionic liquid,poly(p-vinylbenzyl trimethylam-monium hexafluorophosphate)(PTA),and introduce it into the buried interface of PSCs.The quaternary ammonium cation(N(-CH_(3))^(3+))in PTA can fill the vacancies of organic cations within the perovskite structure and reduce shallow energy level defects.Additionally,the hexafluorophosphate(PF6−)in PTA forms a Lewis acid-base interaction with Pb^(2+)in the perovskite layer,effectively passivating deep en-ergy level defects.Furthermore,hydrogen bonding can be established between organic cations and the PF6−anion,preventing the formation of shallow energy level defects.Through this synergistic mecha-nism,the deep and shallow energy level defects are effectively mitigated,resulting in improved device performance.As a result,the resulting treated inverted PSC exhibits an impressive power conversion ef-ficiency(PCE)of 24.72%.Notably,the PTA-treated PSCs exhibit remarkable stability,with 88.5%of the original PCE retained after undergoing heat aging at 85℃ for 1078 h,and 89.1%of the initial PCE main-tained following continuous exposure to light for 1100 h at the maximum power point.Synergistically suppressing multiple defects at the buried interface through the use of polyionic liquids is a promising way to improve the commercial viability of PSCs.
