The finite time thermodynamic performance of a generalized Carnot cycle, in which the heat transfer between the working fluid and the heat reservoirs obeys the generalized law Q∝( Δ T) m , is studied. The optimal ...The finite time thermodynamic performance of a generalized Carnot cycle, in which the heat transfer between the working fluid and the heat reservoirs obeys the generalized law Q∝( Δ T) m , is studied. The optimal configuration and the fundamental optimal relation between power and efficiency of the cycle are derived. Some special examples are discussed. The results can provide some theoretical guidance for the design a practical engine.展开更多
Coals are carbon-rich materials with excellent aromatic nature and macro- molecular structure. They pose great potential as the source of organic chemical feed- stock and high value-added carbonaceous materials in the...Coals are carbon-rich materials with excellent aromatic nature and macro- molecular structure. They pose great potential as the source of organic chemical feed- stock and high value-added carbonaceous materials in the 21st century. As some of the most important analytical methods, thermal analysis (TA) techniques with strong com- petence in materials characterization and reaction mechanism research, have been ex- tensively employed to accumulate the knowledge about coal conversion and utilization in a most effective, efficient and responsible way. Unfortunately, some efforts did not promote the sound growth of a systematic discipline, which might arise from the intrinsic drawback of conventional TA. Proposals on acquiring much more reliable understanding of the mechanism and kinetics of reactions were made in this review.展开更多
Since the 1950s, there have been several food crises with severe humanitarian, economic, political and market-related consequences. In the last decade, food crises occurred during 2007-2008 and again in 2010-2011. In ...Since the 1950s, there have been several food crises with severe humanitarian, economic, political and market-related consequences. In the last decade, food crises occurred during 2007-2008 and again in 2010-2011. In the paper, the main explanations for the food crises are discussed with a focus on the 2007-2008 food crisis, and the main causes are divided into temporary/random and structural/long term and are listed. Although there are a large number of factors, the size of reserves, speculation and bioenergy seem to be significant causes of the rapidly increasing food prices which were a major cause of the food crisis. The consequences of the food crisis in 2007-2008 in particular are discussed, and some major lessons learnt are listed. Also, the present market situation is assessed, the conclusion of which is that there does not seem to be an immediate risk of another food crisis occurring in the short term. However, international cereal reserves are still vulnerable and lower compared to the level in the 1990s.展开更多
The motivation is an employee's internal relationship in the form of behaviour directed towards a specific goal and is manifested as an important factor for overall organisation performance. The goal of any business ...The motivation is an employee's internal relationship in the form of behaviour directed towards a specific goal and is manifested as an important factor for overall organisation performance. The goal of any business is to motivate employees to perform work with the maximum results. The work motivation is complex and dynamic feature of human resources and influences to motivation are very broad and diverse. The material forms of motivation are different compensation that employees receive for their work in the company. They appear in the financial and non-financial forms (paid or in the form of various services). The goal of this research is to identify the main factors of human resources motivation in financial institutions (banks). The questionnaire will be used as a research instrument and consists of two parts. The first part of the questionnaire will focus on socio-demographic characteristics and the second part concentrates on the motivation variables of material and immaterial character. Applying adequate knowledge discovery research methods will be identified as the main motivation components of selling persons in financial institutions.展开更多
This paper summarizes the encrgy consumption of rail transit and the current situation of energy saving. Then it puts forward a number of policy support measures on the technology management from several aspects, such...This paper summarizes the encrgy consumption of rail transit and the current situation of energy saving. Then it puts forward a number of policy support measures on the technology management from several aspects, such as the raft line, traction power supply, energy-saving mode and so on The related research helps urban rail transit enterprises save energy consumption, reduce costs to improve their market competitiveness, as well as to promote the enterprises to fulfill social responsibility and carry out the sustainable development idea.展开更多
The increase in car ownership brought about by energy shortages,and environmental crises became more acute.The most effective way to achieve energy saving and emission reduction of car is to improve engine efficiency....The increase in car ownership brought about by energy shortages,and environmental crises became more acute.The most effective way to achieve energy saving and emission reduction of car is to improve engine efficiency.In addition to that,lightweight body is the key.Aluminum,magnesium alloy as significant materials of lightweight,and the application amount in the car body is a significant upward trend.However,there is high cost of material,with immature applied technology and a series of bottleneck problems.All of them affect general application of lightweight materials. This paper focuses on forming process issues for aluminum,magnesium alloy and the solutions to achieve.展开更多
Graphene shows great potentials in electrochemical energy-related areas.To enhance its properties and corresponding electrochemical performance,recently,three-dimensional(3D)graphene-based materials especially monolit...Graphene shows great potentials in electrochemical energy-related areas.To enhance its properties and corresponding electrochemical performance,recently,three-dimensional(3D)graphene-based materials especially monolithic porous graphene with encapsulated functional nanomaterials have arisen much research interest for electrochemical catalysis,lithium ion batteries(LIBs),lithium–sulfur batteries,supercapacitors,etc.With the enhanced structure properties such as interconnected graphene network,high volume-specific surface area and electronic conductivity,3D monolithic graphene is more suitable for the fabrication of composite electrode materials in real devices.In this article,we discuss recent development in fabricating monolithic 3D graphene and their composites using template-directed methods and their applications in electrochemical energy-related areas.展开更多
Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron accepto...Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron acceptor, and the power conversion efficiency(PCE) of 4.31% has been achieved under AM 1.5 G(100 m W cm^(-2)) illumination condition via optimizing the polymer/PC_(61)BM ratio, the variety of solvent and the spin-coating speed. The impact of the spin-coating speed on the photovoltaic performance of the PSCs has been investigated by revealing the effects of the spin-coating speed on the morphology and the absorption spectra of the polymer/PC_(61)BM blend films. When the thickness of the blend films are adjusted by spin-coating a fixed concentration with different spin-coating speeds, the blend film prepared at a lower spin-coating speed shows a stronger absorption per unit thickness, and the correspond device shows higher IPCE value in the longer-wavelength region. Under the conditions of similar thickness, the blend film prepared at a lower spin-coating speed forms a more uniform microphase separation and smaller domain size which leads to a higher absorption intensity per unit thickness of the blend film in long wavenumber band, a larger short-circuit current density(J_(sc)) and a higher power conversion efficiency(PCE) of the PSC device. Noteworthily, it was found that spin-coating speed is not only a way to control the thickness of active layer but also an influencing factor on morphology and photovoltaic performance for the diketopyrrolopyrrole-based terpolymer.展开更多
Neural information processing is tightly coupled to both energy consumption and derivation from substrates.In this study,the energy function of the neuron during the action potential(AP)is described and analyzed.It ha...Neural information processing is tightly coupled to both energy consumption and derivation from substrates.In this study,the energy function of the neuron during the action potential(AP)is described and analyzed.It has been observed that energy consumption during the AP does not match predictions of the conventional theory of neural energy dynamics.On short time scales,neural energy expenditure shifts between positive and negative phases.During the AP,the energy source switches from neuronal stores(positive expenditure or net consumption)to exploitation of external substrates,specifically the glucose and oxygen carried in cerebral blood(the negative consumption phase).Based on the idea of reductionism,this paper demonstrates how ion channels,membrane pumps and transporters,ionotropic and metabotropic receptor signaling pathways,astrocyte glycolysis and the production lactate,and the glutamate-glutamine cycle all serve to relate cerebral blood flow and neuronal metabolism to neuronal activity and so maintain neuronal energy charge during the AP.展开更多
文摘The finite time thermodynamic performance of a generalized Carnot cycle, in which the heat transfer between the working fluid and the heat reservoirs obeys the generalized law Q∝( Δ T) m , is studied. The optimal configuration and the fundamental optimal relation between power and efficiency of the cycle are derived. Some special examples are discussed. The results can provide some theoretical guidance for the design a practical engine.
文摘Coals are carbon-rich materials with excellent aromatic nature and macro- molecular structure. They pose great potential as the source of organic chemical feed- stock and high value-added carbonaceous materials in the 21st century. As some of the most important analytical methods, thermal analysis (TA) techniques with strong com- petence in materials characterization and reaction mechanism research, have been ex- tensively employed to accumulate the knowledge about coal conversion and utilization in a most effective, efficient and responsible way. Unfortunately, some efforts did not promote the sound growth of a systematic discipline, which might arise from the intrinsic drawback of conventional TA. Proposals on acquiring much more reliable understanding of the mechanism and kinetics of reactions were made in this review.
文摘Since the 1950s, there have been several food crises with severe humanitarian, economic, political and market-related consequences. In the last decade, food crises occurred during 2007-2008 and again in 2010-2011. In the paper, the main explanations for the food crises are discussed with a focus on the 2007-2008 food crisis, and the main causes are divided into temporary/random and structural/long term and are listed. Although there are a large number of factors, the size of reserves, speculation and bioenergy seem to be significant causes of the rapidly increasing food prices which were a major cause of the food crisis. The consequences of the food crisis in 2007-2008 in particular are discussed, and some major lessons learnt are listed. Also, the present market situation is assessed, the conclusion of which is that there does not seem to be an immediate risk of another food crisis occurring in the short term. However, international cereal reserves are still vulnerable and lower compared to the level in the 1990s.
文摘The motivation is an employee's internal relationship in the form of behaviour directed towards a specific goal and is manifested as an important factor for overall organisation performance. The goal of any business is to motivate employees to perform work with the maximum results. The work motivation is complex and dynamic feature of human resources and influences to motivation are very broad and diverse. The material forms of motivation are different compensation that employees receive for their work in the company. They appear in the financial and non-financial forms (paid or in the form of various services). The goal of this research is to identify the main factors of human resources motivation in financial institutions (banks). The questionnaire will be used as a research instrument and consists of two parts. The first part of the questionnaire will focus on socio-demographic characteristics and the second part concentrates on the motivation variables of material and immaterial character. Applying adequate knowledge discovery research methods will be identified as the main motivation components of selling persons in financial institutions.
文摘This paper summarizes the encrgy consumption of rail transit and the current situation of energy saving. Then it puts forward a number of policy support measures on the technology management from several aspects, such as the raft line, traction power supply, energy-saving mode and so on The related research helps urban rail transit enterprises save energy consumption, reduce costs to improve their market competitiveness, as well as to promote the enterprises to fulfill social responsibility and carry out the sustainable development idea.
文摘The increase in car ownership brought about by energy shortages,and environmental crises became more acute.The most effective way to achieve energy saving and emission reduction of car is to improve engine efficiency.In addition to that,lightweight body is the key.Aluminum,magnesium alloy as significant materials of lightweight,and the application amount in the car body is a significant upward trend.However,there is high cost of material,with immature applied technology and a series of bottleneck problems.All of them affect general application of lightweight materials. This paper focuses on forming process issues for aluminum,magnesium alloy and the solutions to achieve.
基金supported by Thousand Young Talents Program of the Chinese Central Government (0220002 102003)the National Natural Science Foundation of China (21373280)+2 种基金Beijing National Laboratory for Molecular Sciences (BNLMS)Hundred Talents Program at Chongqing University (0903005203205)Chongqing Basic and Frontier Research Project (cstc2015jcyj A50026)
文摘Graphene shows great potentials in electrochemical energy-related areas.To enhance its properties and corresponding electrochemical performance,recently,three-dimensional(3D)graphene-based materials especially monolithic porous graphene with encapsulated functional nanomaterials have arisen much research interest for electrochemical catalysis,lithium ion batteries(LIBs),lithium–sulfur batteries,supercapacitors,etc.With the enhanced structure properties such as interconnected graphene network,high volume-specific surface area and electronic conductivity,3D monolithic graphene is more suitable for the fabrication of composite electrode materials in real devices.In this article,we discuss recent development in fabricating monolithic 3D graphene and their composites using template-directed methods and their applications in electrochemical energy-related areas.
基金supported by the National Natural Science Foundation of China (51573153)the Natural Science Foundation of Hunan Province of China (2015JJ2141)+1 种基金the Scientific Research Foundation of the State Education Ministry for the Returned Overseas Chinese Scholars (2014–1685)the Scientific Research Fund of Hunan Provincial Education Department (15A180)
文摘Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron acceptor, and the power conversion efficiency(PCE) of 4.31% has been achieved under AM 1.5 G(100 m W cm^(-2)) illumination condition via optimizing the polymer/PC_(61)BM ratio, the variety of solvent and the spin-coating speed. The impact of the spin-coating speed on the photovoltaic performance of the PSCs has been investigated by revealing the effects of the spin-coating speed on the morphology and the absorption spectra of the polymer/PC_(61)BM blend films. When the thickness of the blend films are adjusted by spin-coating a fixed concentration with different spin-coating speeds, the blend film prepared at a lower spin-coating speed shows a stronger absorption per unit thickness, and the correspond device shows higher IPCE value in the longer-wavelength region. Under the conditions of similar thickness, the blend film prepared at a lower spin-coating speed forms a more uniform microphase separation and smaller domain size which leads to a higher absorption intensity per unit thickness of the blend film in long wavenumber band, a larger short-circuit current density(J_(sc)) and a higher power conversion efficiency(PCE) of the PSC device. Noteworthily, it was found that spin-coating speed is not only a way to control the thickness of active layer but also an influencing factor on morphology and photovoltaic performance for the diketopyrrolopyrrole-based terpolymer.
基金supported by the National Natural Science Foundation of China(Grant Nos.1123200511002055)the Ministry of Education Doctoral Foundation(Grant No.20120074110020)
文摘Neural information processing is tightly coupled to both energy consumption and derivation from substrates.In this study,the energy function of the neuron during the action potential(AP)is described and analyzed.It has been observed that energy consumption during the AP does not match predictions of the conventional theory of neural energy dynamics.On short time scales,neural energy expenditure shifts between positive and negative phases.During the AP,the energy source switches from neuronal stores(positive expenditure or net consumption)to exploitation of external substrates,specifically the glucose and oxygen carried in cerebral blood(the negative consumption phase).Based on the idea of reductionism,this paper demonstrates how ion channels,membrane pumps and transporters,ionotropic and metabotropic receptor signaling pathways,astrocyte glycolysis and the production lactate,and the glutamate-glutamine cycle all serve to relate cerebral blood flow and neuronal metabolism to neuronal activity and so maintain neuronal energy charge during the AP.