Rare earths,as a strategic mineral resource,play a vital role in high-tech industries such as aerospace,national defense and military,electronic information,and new energy.With the accelerated evolution of the new rou...Rare earths,as a strategic mineral resource,play a vital role in high-tech industries such as aerospace,national defense and military,electronic information,and new energy.With the accelerated evolution of the new round of technological revolution and industrial transformation,global supply chain security risks have become more prominent.The focus of major countries'resource security assurance has also shifted from bulk minerals to critical minerals.展开更多
This study investigates the earnings performance of 418 initial public offerings （IPOs） listed on the stock exchange of Hong Kong. By analyzing several profitability measures of these 1PO companies from the third ye...This study investigates the earnings performance of 418 initial public offerings （IPOs） listed on the stock exchange of Hong Kong. By analyzing several profitability measures of these 1PO companies from the third year prior to listing up to the fifth year post-listing, it is found that IPO companies＇ operating performances as a whole peak in the year of listing or the year preceding the listing, but exhibit a fall in post-issue profitability with the decline being most pronounced in the first financial year following the year in which the listing take place. Over 30% of these IPOs suffer a loss three years after the offerings. Deterioration of post-issue performance is found to be more severe for smaller finns, highly-geared companies, fast-growing enterprises, companies with lower ownership retention by original shareholders, and companies which have managed earnings upwards at the time of listing. These observations are consistent with the higher agency costs when firms go public and that managers have timed the issue at the peak of the companies＇ long-run performance. Further investigation confirms that IPO companies in general make use of income-increasing accruals to manage their earnings upwards in the year when they go public. The reversal of the accruals in post-issue years further exaggerates the decline in their profitability.展开更多
As the development of economy, the corporate social responsibility （CSR） received more and more recognition from academic and business. The traditional economy with only goal of pursuing the wealth is changing rapi...As the development of economy, the corporate social responsibility （CSR） received more and more recognition from academic and business. The traditional economy with only goal of pursuing the wealth is changing rapidly. Chinese corporations realize that it is important and urgent to value the social responsibility, search for effective means to balance the relationship between CSR and COP （corporate operating performance）. Meanwhile, it is helpful and meaningful for the society to build up a healthy and appropriate operating value for corporations. However, there is always a debate of how many social responsibilities a corporation should take in order to satisfy the corporate development and the relationship between CSR and profit, and previous researches on corporate social responsibility mainly focused on all stakeholders of a company. As more and more corporations are aware of the importance of their employee, this study specifically selects employee, one of the most important stakeholders, as the subject investigated. Meanwhile, it chooses New Era Health Industry （Group） Co., Ltd as the target enterprise, which is the only state-owned key enterprises in health industry and the leading corporation in directselling industry in China's Mainland. In order to research the relationship between corporate operating performance and the satisfaction of employees’ material needs and psychological needs, this study plans to complete it by combining the theoretical and empirical study, qualitative analysis and quantitative analysis research methods. Based on a questionnaire of 200 employees in New Era, this study analyzes the situation of CSR to employees for New Era and comes to the conclusion of the relationship between the CSR and COP. According to the research result, this study may give some suggestions for Chinese corporations to fulfill their socialresponsibility system and to improve the situation of the lack of CSR to employees.展开更多
The banking industry is placing increasing emphasis on green finance to address climate change,support sustainable development,and align with environmental,social,and governance(ESG)goals,as well as sustainable invest...The banking industry is placing increasing emphasis on green finance to address climate change,support sustainable development,and align with environmental,social,and governance(ESG)goals,as well as sustainable investments to fund environmentally friendly projects.In an era of growing regulatory pressure and rising demand for sustainability from investors and stakeholders,green finance has become a vital tool for banks to enhance operational efficiency.It can reduce operational costs by financing energy-saving projects,improve asset quality by funding low-risk sustainable projects,and even attract capital from environmentally responsible capital markets.Additionally,green finance helps improve risk management frameworks by financing projects that align with long-term sustainable development objectives.This paper explores the relationship between green finance and the operational efficiency of three major banks—RHB Bank,Industrial and Commercial Bank of China(ICBC),and Deutsche Bank.The article focuses on analyzing how these banks integrate green finance into their strategies and the overall impact of these initiatives on operational performance,primarily cost reduction.展开更多
The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and p...The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.展开更多
Currently,the operational performance assessment system in the power market primarily focuses on power generation and electricity retail companies,lacking a system tailored to the operational characteristics of power ...Currently,the operational performance assessment system in the power market primarily focuses on power generation and electricity retail companies,lacking a system tailored to the operational characteristics of power generation/selling integrated companies.Therefore,this article proposes an assessment index system for assessing the operational performance of a power generation/selling integrated company,encompassing three dimensions:basic capacity,development potential,and external environment.A dynamic proportional adjustment coefficient is designed,along with a subjective and objective weighting model for assessment indexes based on a combined weightingmethod.Subsequently,the operational performance of an integrated company is assessed using extension theory.The results in the case study demonstrate the feasibility and effectiveness of the proposed dynamic proportional adjustment coefficient.展开更多
Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, i...Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, it is held that, the notable energy imbalance of furnace exit, ever existing in the tangential firing boilers has been solved, with comparatively lower NOX emission concentration of gained. The higher NOX emission concentration and furnace slagging etc. problems existing in wall firing boilers are notable. The comprehensive analysis shows that, it is appropriate to choose lower furnace volume heat release rate and higher flame height in the type selection design of boilers, and sufficient margin should be kept in the selection of coal pulverizing mills.展开更多
An experimental study was carried out in this article to investigate the transient operating performance of a Dual Compensation Chamber Loop Heat Pipe(DCCLHP) with Thermoelectric Cooler(TEC) under acceleration conditi...An experimental study was carried out in this article to investigate the transient operating performance of a Dual Compensation Chamber Loop Heat Pipe(DCCLHP) with Thermoelectric Cooler(TEC) under acceleration conditions and ammonia was selected as the working fluid.For the purpose of comparison, experimental work was conducted under terrestrial gravity.Sensitivity analysis was performed to explore the effect of several control parameters such as the heat load, acceleration magnitude and TEC assist on the startup and operating performance of the DCCLHP.Experimental results indicate that the DCCLHP can get to a steady-state operation when the heat load changes from 25 W to 300 W under terrestrial gravity.While under acceleration conditions, the DCCLHP can work at a high operating temperature or even fail to operate, which shows the acceleration effect plays a significant impact on the loop operation.The TEC assist with power of 10 W can improve the operating performance and reduce the operating temperature for the case of small heat load and acceleration magnitude.When the acceleration exceeds 3 g at large heat load, the effect of TEC assist on the operation at large heat load can be ignored.展开更多
Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column（OWC） wave energy converters, which can rotate in the same direction under the bi-directional air f...Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column（OWC） wave energy converters, which can rotate in the same direction under the bi-directional air flows. A numerical model established in Fluent is validated by the corresponding experimental results. The flow fields, pressure distribution and dimensionless evaluating coefficients can be calculated and analyzed. Effects of the rotor solidity varying with the change of blade number are investigated and the suitable solidity value is recommended for different flow coefficients.展开更多
Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization....Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization.In this context,mechanical properties have emerged as critical parameters for evaluating the operational performance and longevity of materials and devices at the micro/nanoscale.展开更多
In this paper, the operating performances of the main commercial banks＇ information security management system applications are empirically researched using the DEA method of operating efficiency＇s multi-stage super...In this paper, the operating performances of the main commercial banks＇ information security management system applications are empirically researched using the DEA method of operating efficiency＇s multi-stage super efficiency. The DEA model of multi-stage super efficiency is established for the commercial bank information security system applications of China＇s banks using data envelopment analysis （DEA）, and then output efficiency, taxation efficiency, and comprehensive efficiency are analyzed by choosing eight banks such as Industrial and Commercial bank of China as sample data, and finally the operating performance of Chinese commercial banks＇ information security management system is concluded.展开更多
The operational performance of a full scale subsurface flow constructed wetland, which treated the mixed industrial and domestic wastewater with BOD 5/COD mean ratio of 0 33 at Shatian, Shenzhen City was studied. ...The operational performance of a full scale subsurface flow constructed wetland, which treated the mixed industrial and domestic wastewater with BOD 5/COD mean ratio of 0 33 at Shatian, Shenzhen City was studied. The constructed wetland system consists of screens, sump, pumping station, and primary settling basin, facultative pond, first stage wetland and secondary stage wetland. The designed treatment capacity is 5000 m 3/d, and the actual influent flow is in the range of <2000 to >10000 m 3/d. Under normal operational conditions, the final effluent quality well met the National Integrated Wastewater Discharge Standard(GB 8978\_1996), with the following parameters(mean values): COD 33 90 mg/L, BOD 5 7.65 mg/L, TSS 7.92 mg/L, TN 9.11 mg/L and TP 0 56 mg/L. Seven species of plants were selected to grow in the wetland: Reed, Sweetcane flower Silvergrass, Great Bulrush, Powdery Thalia and Canna of three colours. The growing season is a whole year round. The seasonal discrepancy could be observed and the plants growing in the wetland are vulnerable to lower temperature in winter. The recycling of the effluent in the first stage of the wetland system is an effective measure to improve the performance of the wetland system. The insufficient DO value in the wetland system not only had significant effect on pollutants removal in the wetland, but also was unfavourable to plant growth. The recycling of effluent to the inlet of wetland system and artificial pond to increase DO value of influent to the wetland is key to operate the subsurface constructed wetland steadily and effectively.展开更多
Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this co...Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this combustion technology.In the present study,the RDC operation performance with a turbine guide vane(TGV)is experimentally investigated.Hydrogen and air are used as propellants while hydrogen and air mass flow rate are about 16.1 g/s and 500 g/s and the equivalence ratio is about 1.0.A pre-detonator is used to ignite the mixture.High-frequency dynamic pressure transducers and silicon pressure sensors are employed to measure pressure oscillations and static pressure in the combustion chamber.The experimental results show that the steady propagation of rotating detonation wave(RDW)is observed in the combustion chamber and the mean propagation velocity is above 1650 m/s,reaching over 84%of theoretical Chapman-Jouguet detonation velocity.Clockwise and counterclockwise propagation directions of RDW are obtained.For clockwise propagation direction,the static pressure is about 15%higher in the combustor compared with counterclockwise propagation direction,but the RDW dominant frequency is lower.When the oblique shock wave propagates across the TGV,the pressure oscillations reduces significantly.In addition,as the detonation products flow through the TGV,the static pressure drops up to 32%and 43%for clockwise and counterclockwise propagation process respectively.展开更多
The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is...The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.展开更多
In situations where discontinuity in operation occurs, specifically in a country where coontractualization has an increasing trend, the performance level of operators after the work break is of great interest. Existin...In situations where discontinuity in operation occurs, specifically in a country where coontractualization has an increasing trend, the performance level of operators after the work break is of great interest. Existing studies have found that the performance of an operator declines after her operation is completely stopped. However, when the operator performed other tasks （may it be similar or not from her previous task） during the work break, the performance after the work break seems to be affected at different level. Contractual and regular operators from a semiconductor and textile company were considered to replicate a discontinuous and continuous operation. The processing times of contractual workers before and after several months of work break were compared. Two types of work break were seen to have significant effect on an operator＇s performance after the work break, Type 1： 0% to 40% similarity from previous task and Type 2： 40% to 97% similarity from previous task. One can find that when 21% of tasks performed during the work break are similar to the operator＇s previous task, there would be no change in her performance upon returning. On the other hand, a 5% decline in performance was observed after work break type 1 and an 8.54% improvement after work break type 2. Also, a remission rate of 18% from end of stint 1 to start of stint 2 under work break type 1 was seen, while 8% for work break type 2. This may also be true to other industries. Thus, further study is suggested.展开更多
This paper selected the corn processing industry technology innovation alliance in Heilongjiang Province as the research object, evaluated the operational performance of the alliance by using analytic hierarchy proces...This paper selected the corn processing industry technology innovation alliance in Heilongjiang Province as the research object, evaluated the operational performance of the alliance by using analytic hierarchy process(AHP) and fuzzy comprehensive evaluation methods. AHP empirical results showed that the satisfaction of information communication and the satisfaction of the management process were the weakest. And the order from high to low on the level of indicators of the impact for the alliance was the result of alliance operations and the process of alliance operations, the behavioral attitude of alliance members. Besides, the results of fuzzy comprehensive evaluation showed that the operational performance of the corn processing industry technology innovation alliance in Heilongjiang Province was in the general level.展开更多
The main way they have of improving overall system reliability is to concentrate on human reliability if organizations are not installing new plant. Previous research by the author has shown that the main cause of sys...The main way they have of improving overall system reliability is to concentrate on human reliability if organizations are not installing new plant. Previous research by the author has shown that the main cause of system unreliability is operator unreliability. There are three main ways to deal with operator unreliability viz improve the environment, enhance the operator′s skill and increase his motivation. Of these, the last is the final untapped area for achieving significant gains in system reliability. Moves to do this by means of competitions for operators at both a local and international level are discussed, with a description of the successes so far.展开更多
In the paper, the method to optimize the rotor structure in variable frequency speed control motors is introduced. The saturation and the skin effect are considered and 2D no-load and load electromagnetic field is cal...In the paper, the method to optimize the rotor structure in variable frequency speed control motors is introduced. The saturation and the skin effect are considered and 2D no-load and load electromagnetic field is calculated in finite elements for a variable frequency speed control motor before and after optimization. Finally, no-load current and operation performance before and after optimization are obtained and the two results are contrasted.展开更多
文摘Rare earths,as a strategic mineral resource,play a vital role in high-tech industries such as aerospace,national defense and military,electronic information,and new energy.With the accelerated evolution of the new round of technological revolution and industrial transformation,global supply chain security risks have become more prominent.The focus of major countries'resource security assurance has also shifted from bulk minerals to critical minerals.
文摘This study investigates the earnings performance of 418 initial public offerings （IPOs） listed on the stock exchange of Hong Kong. By analyzing several profitability measures of these 1PO companies from the third year prior to listing up to the fifth year post-listing, it is found that IPO companies＇ operating performances as a whole peak in the year of listing or the year preceding the listing, but exhibit a fall in post-issue profitability with the decline being most pronounced in the first financial year following the year in which the listing take place. Over 30% of these IPOs suffer a loss three years after the offerings. Deterioration of post-issue performance is found to be more severe for smaller finns, highly-geared companies, fast-growing enterprises, companies with lower ownership retention by original shareholders, and companies which have managed earnings upwards at the time of listing. These observations are consistent with the higher agency costs when firms go public and that managers have timed the issue at the peak of the companies＇ long-run performance. Further investigation confirms that IPO companies in general make use of income-increasing accruals to manage their earnings upwards in the year when they go public. The reversal of the accruals in post-issue years further exaggerates the decline in their profitability.
文摘As the development of economy, the corporate social responsibility （CSR） received more and more recognition from academic and business. The traditional economy with only goal of pursuing the wealth is changing rapidly. Chinese corporations realize that it is important and urgent to value the social responsibility, search for effective means to balance the relationship between CSR and COP （corporate operating performance）. Meanwhile, it is helpful and meaningful for the society to build up a healthy and appropriate operating value for corporations. However, there is always a debate of how many social responsibilities a corporation should take in order to satisfy the corporate development and the relationship between CSR and profit, and previous researches on corporate social responsibility mainly focused on all stakeholders of a company. As more and more corporations are aware of the importance of their employee, this study specifically selects employee, one of the most important stakeholders, as the subject investigated. Meanwhile, it chooses New Era Health Industry （Group） Co., Ltd as the target enterprise, which is the only state-owned key enterprises in health industry and the leading corporation in directselling industry in China's Mainland. In order to research the relationship between corporate operating performance and the satisfaction of employees’ material needs and psychological needs, this study plans to complete it by combining the theoretical and empirical study, qualitative analysis and quantitative analysis research methods. Based on a questionnaire of 200 employees in New Era, this study analyzes the situation of CSR to employees for New Era and comes to the conclusion of the relationship between the CSR and COP. According to the research result, this study may give some suggestions for Chinese corporations to fulfill their socialresponsibility system and to improve the situation of the lack of CSR to employees.
文摘The banking industry is placing increasing emphasis on green finance to address climate change,support sustainable development,and align with environmental,social,and governance(ESG)goals,as well as sustainable investments to fund environmentally friendly projects.In an era of growing regulatory pressure and rising demand for sustainability from investors and stakeholders,green finance has become a vital tool for banks to enhance operational efficiency.It can reduce operational costs by financing energy-saving projects,improve asset quality by funding low-risk sustainable projects,and even attract capital from environmentally responsible capital markets.Additionally,green finance helps improve risk management frameworks by financing projects that align with long-term sustainable development objectives.This paper explores the relationship between green finance and the operational efficiency of three major banks—RHB Bank,Industrial and Commercial Bank of China(ICBC),and Deutsche Bank.The article focuses on analyzing how these banks integrate green finance into their strategies and the overall impact of these initiatives on operational performance,primarily cost reduction.
基金Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization(South China University of Technology)(2013A061401005)Research Fund(JMSWFW-2110-044)from Zhongshan Jiaming Electric Power Co.,Ltd.
文摘The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.
基金supported in part by the Science and Technology Innovation Program of Hunan Province under Grants 2023JJ40046 and 2023JJ30049.
文摘Currently,the operational performance assessment system in the power market primarily focuses on power generation and electricity retail companies,lacking a system tailored to the operational characteristics of power generation/selling integrated companies.Therefore,this article proposes an assessment index system for assessing the operational performance of a power generation/selling integrated company,encompassing three dimensions:basic capacity,development potential,and external environment.A dynamic proportional adjustment coefficient is designed,along with a subjective and objective weighting model for assessment indexes based on a combined weightingmethod.Subsequently,the operational performance of an integrated company is assessed using extension theory.The results in the case study demonstrate the feasibility and effectiveness of the proposed dynamic proportional adjustment coefficient.
文摘Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, it is held that, the notable energy imbalance of furnace exit, ever existing in the tangential firing boilers has been solved, with comparatively lower NOX emission concentration of gained. The higher NOX emission concentration and furnace slagging etc. problems existing in wall firing boilers are notable. The comprehensive analysis shows that, it is appropriate to choose lower furnace volume heat release rate and higher flame height in the type selection design of boilers, and sufficient margin should be kept in the selection of coal pulverizing mills.
基金the financial supports from the Fundamental Research Funds for the Central Universities of China(YWF-14-HKXY-019)。
文摘An experimental study was carried out in this article to investigate the transient operating performance of a Dual Compensation Chamber Loop Heat Pipe(DCCLHP) with Thermoelectric Cooler(TEC) under acceleration conditions and ammonia was selected as the working fluid.For the purpose of comparison, experimental work was conducted under terrestrial gravity.Sensitivity analysis was performed to explore the effect of several control parameters such as the heat load, acceleration magnitude and TEC assist on the startup and operating performance of the DCCLHP.Experimental results indicate that the DCCLHP can get to a steady-state operation when the heat load changes from 25 W to 300 W under terrestrial gravity.While under acceleration conditions, the DCCLHP can work at a high operating temperature or even fail to operate, which shows the acceleration effect plays a significant impact on the loop operation.The TEC assist with power of 10 W can improve the operating performance and reduce the operating temperature for the case of small heat load and acceleration magnitude.When the acceleration exceeds 3 g at large heat load, the effect of TEC assist on the operation at large heat load can be ignored.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51279190 and 51311140259)the Shandong Province Natural Science Foundation for Distinguished Young Scholars(Grant No.JQ201314)
文摘Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column（OWC） wave energy converters, which can rotate in the same direction under the bi-directional air flows. A numerical model established in Fluent is validated by the corresponding experimental results. The flow fields, pressure distribution and dimensionless evaluating coefficients can be calculated and analyzed. Effects of the rotor solidity varying with the change of blade number are investigated and the suitable solidity value is recommended for different flow coefficients.
文摘Over the past three decades,micro/nano science and technology have experienced rapid advancements as new materials and advanced devices have increasingly evolved towards high levels of integration and miniaturization.In this context,mechanical properties have emerged as critical parameters for evaluating the operational performance and longevity of materials and devices at the micro/nanoscale.
文摘In this paper, the operating performances of the main commercial banks＇ information security management system applications are empirically researched using the DEA method of operating efficiency＇s multi-stage super efficiency. The DEA model of multi-stage super efficiency is established for the commercial bank information security system applications of China＇s banks using data envelopment analysis （DEA）, and then output efficiency, taxation efficiency, and comprehensive efficiency are analyzed by choosing eight banks such as Industrial and Commercial bank of China as sample data, and finally the operating performance of Chinese commercial banks＇ information security management system is concluded.
文摘The operational performance of a full scale subsurface flow constructed wetland, which treated the mixed industrial and domestic wastewater with BOD 5/COD mean ratio of 0 33 at Shatian, Shenzhen City was studied. The constructed wetland system consists of screens, sump, pumping station, and primary settling basin, facultative pond, first stage wetland and secondary stage wetland. The designed treatment capacity is 5000 m 3/d, and the actual influent flow is in the range of <2000 to >10000 m 3/d. Under normal operational conditions, the final effluent quality well met the National Integrated Wastewater Discharge Standard(GB 8978\_1996), with the following parameters(mean values): COD 33 90 mg/L, BOD 5 7.65 mg/L, TSS 7.92 mg/L, TN 9.11 mg/L and TP 0 56 mg/L. Seven species of plants were selected to grow in the wetland: Reed, Sweetcane flower Silvergrass, Great Bulrush, Powdery Thalia and Canna of three colours. The growing season is a whole year round. The seasonal discrepancy could be observed and the plants growing in the wetland are vulnerable to lower temperature in winter. The recycling of the effluent in the first stage of the wetland system is an effective measure to improve the performance of the wetland system. The insufficient DO value in the wetland system not only had significant effect on pollutants removal in the wetland, but also was unfavourable to plant growth. The recycling of effluent to the inlet of wetland system and artificial pond to increase DO value of influent to the wetland is key to operate the subsurface constructed wetland steadily and effectively.
基金the National Natural Science Foundation of China(No.11702143 and 11802137)the Fundamental Research Funds for the Central Universities(No.30918011343 and 30919011259).
文摘Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this combustion technology.In the present study,the RDC operation performance with a turbine guide vane(TGV)is experimentally investigated.Hydrogen and air are used as propellants while hydrogen and air mass flow rate are about 16.1 g/s and 500 g/s and the equivalence ratio is about 1.0.A pre-detonator is used to ignite the mixture.High-frequency dynamic pressure transducers and silicon pressure sensors are employed to measure pressure oscillations and static pressure in the combustion chamber.The experimental results show that the steady propagation of rotating detonation wave(RDW)is observed in the combustion chamber and the mean propagation velocity is above 1650 m/s,reaching over 84%of theoretical Chapman-Jouguet detonation velocity.Clockwise and counterclockwise propagation directions of RDW are obtained.For clockwise propagation direction,the static pressure is about 15%higher in the combustor compared with counterclockwise propagation direction,but the RDW dominant frequency is lower.When the oblique shock wave propagates across the TGV,the pressure oscillations reduces significantly.In addition,as the detonation products flow through the TGV,the static pressure drops up to 32%and 43%for clockwise and counterclockwise propagation process respectively.
基金Project(2012BAJ06B04)supported by"12th Five-Year Plan"National science and Technology,ChinaProject(2014-228)supported by Department of Housing and Urban Rural Development of Hebei,China
文摘The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.
文摘In situations where discontinuity in operation occurs, specifically in a country where coontractualization has an increasing trend, the performance level of operators after the work break is of great interest. Existing studies have found that the performance of an operator declines after her operation is completely stopped. However, when the operator performed other tasks （may it be similar or not from her previous task） during the work break, the performance after the work break seems to be affected at different level. Contractual and regular operators from a semiconductor and textile company were considered to replicate a discontinuous and continuous operation. The processing times of contractual workers before and after several months of work break were compared. Two types of work break were seen to have significant effect on an operator＇s performance after the work break, Type 1： 0% to 40% similarity from previous task and Type 2： 40% to 97% similarity from previous task. One can find that when 21% of tasks performed during the work break are similar to the operator＇s previous task, there would be no change in her performance upon returning. On the other hand, a 5% decline in performance was observed after work break type 1 and an 8.54% improvement after work break type 2. Also, a remission rate of 18% from end of stint 1 to start of stint 2 under work break type 1 was seen, while 8% for work break type 2. This may also be true to other industries. Thus, further study is suggested.
基金Supported by Technology Research and Development Project of Heilongjiang Province(GB14D202)
文摘This paper selected the corn processing industry technology innovation alliance in Heilongjiang Province as the research object, evaluated the operational performance of the alliance by using analytic hierarchy process(AHP) and fuzzy comprehensive evaluation methods. AHP empirical results showed that the satisfaction of information communication and the satisfaction of the management process were the weakest. And the order from high to low on the level of indicators of the impact for the alliance was the result of alliance operations and the process of alliance operations, the behavioral attitude of alliance members. Besides, the results of fuzzy comprehensive evaluation showed that the operational performance of the corn processing industry technology innovation alliance in Heilongjiang Province was in the general level.
文摘The main way they have of improving overall system reliability is to concentrate on human reliability if organizations are not installing new plant. Previous research by the author has shown that the main cause of system unreliability is operator unreliability. There are three main ways to deal with operator unreliability viz improve the environment, enhance the operator′s skill and increase his motivation. Of these, the last is the final untapped area for achieving significant gains in system reliability. Moves to do this by means of competitions for operators at both a local and international level are discussed, with a description of the successes so far.
文摘In the paper, the method to optimize the rotor structure in variable frequency speed control motors is introduced. The saturation and the skin effect are considered and 2D no-load and load electromagnetic field is calculated in finite elements for a variable frequency speed control motor before and after optimization. Finally, no-load current and operation performance before and after optimization are obtained and the two results are contrasted.
