Climate change caused by carbon emissions is a hot topic of concern.Enhancing carbon emission performance(CEP)emerges as a pivotal strategy to curtail carbon emissions,with the digital economy recognized as a crucial ...Climate change caused by carbon emissions is a hot topic of concern.Enhancing carbon emission performance(CEP)emerges as a pivotal strategy to curtail carbon emissions,with the digital economy recognized as a crucial instrument for bolstering CEP.Grounded in theoretical analysis,this article takes the Yangtze River Delta region(YRD)as the research object and conducts empirical analysis for the period from 2010 to 2021.The Super Epsilon-Based Measure(EBM)model was employed to assess CEP,while the entropy method was used to quantify the level of the digital economy.Baseline regression models and mediation effect models were constructed to test the research hypotheses.Additionally,the Spatial Durbin Model(SDM)was utilized to analyze the spatial spillover effects of the digital economy.Some conclusions were drawn as follows.Firstly,both the digital economy and CEP exhibit growing trends and demonstrate significant spatial distribution characteristics.Cities with high CEP are increasingly concentrated along the Yangtze River and coastal areas.Meanwhile,the digital economy generally demonstrates a spatial distribution pattern of being higher in the southeast and lower in the northwest.Secondly,the digital economy exerts a notable and consistent positive influence on CEP,but this impact is not primarily achieved through promoting green technology innovation.Instead,the digital economy exhibits a stronger intermediary effect on CEP by facilitating industrial structure upgrading and rationalization.Thirdly,the digital economy significantly enhancing local CEP but having an insignificant impact on neighboring cities'CEP.To address these findings,cities ought to invest in digital infrastructure,incentivize digital innovation through policy and financial backing,and harness advanced technologies like 5G and blockchain to promote low-carbon,intelligent production and lifestyles,while enhancing industrial structure and regional cooperation to foster a low-carbon digital economy network.展开更多
Carbon emission reduction is the only way to alleviate environmental problems,such as global warming.Effective evaluation of carbon performance can help enterprises to carry out energy saving and emission reduction ac...Carbon emission reduction is the only way to alleviate environmental problems,such as global warming.Effective evaluation of carbon performance can help enterprises to carry out energy saving and emission reduction activities to a certain extent and promote sustainable development.This paper constructs a carbon performance evaluation index system that includes the four dimensions of carbon resource(energy)input,cycle,output,and carbon management by incorporating the principles of circular economy and the theory of resource value circulation from the perspective of the flow trajectory of carbon-containing resources in the circulation of enterprises combined with the production characteristics of thermoelectric enterprises.Subsequently,combined with the case study,this paper discusses the scientific and practical nature of the system and provides another way of thinking for carbon performance evaluation of micro-enterprises in other industries.This paper expands the application boundary of matter-element model and supplements the literature of carbon performance,which has certain theoretical and practical significance.展开更多
Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid an...Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization’s carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.展开更多
Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with...Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with 20 wt% loading has a homogeneous dispersion of Pt nanoparticles with the average size of 3.3 nm, which is smaller than 4.3 and 4.9 nm for the control catalysts with the same loading supported on hierarchical carbon nanocages （hCNC） and commercial Vulcan XC-72, respec- tively. Accordingly, Pt/hNCNC has a larger electrochemical surface area than Pt/hCNC and Pt/XC-72. The Pt/hNCNC catalyst exhibited excellent electrocatalytic activity and stability for methanol oxidation, which was better than the control catalysts. This was attributed to the en- hanced interaction between Pt and hNCNC due to nitrogen participation in the anchoring function. By making use of the unique advantages of the hNCNC support, a heavy Pt loading up to 60 wt% was prepared without serious agglomeration, which gave a high peak-current density per unit mass of catalyst of 95.6 mA/mg for achieving a high power density. These results showed the potential of the Pt/hNCNC catalyst for methanol oxidation and of the new hNCNC support for wide applications.展开更多
Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid an...Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization's carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.展开更多
Climate change resulting from CO_2 emissions has become an important global environmental issue in recent years.Improving carbon emission performance is one way to reduce carbon emissions.Although carbon emission perf...Climate change resulting from CO_2 emissions has become an important global environmental issue in recent years.Improving carbon emission performance is one way to reduce carbon emissions.Although carbon emission performance has been discussed at the national and industrial levels,city-level studies are lacking due to the limited availability of statistics on energy consumption.In this study,based on city-level remote sensing data on carbon emissions in China from 1992–2013,we used the slacks-based measure of super-efficiency to evaluate urban carbon emission performance.The traditional Markov probability transfer matrix and spatial Markov probability transfer matrix were constructed to explore the spatiotemporal evolution of urban carbon emission performance in China for the first time and predict long-term trends in carbon emission performance.The results show that urban carbon emission performance in China steadily increased during the study period with some fluctuations.However,the overall level of carbon emission performance remains low,indicating great potential for improvements in energy conservation and emission reduction.The spatial pattern of urban carbon emission performance in China can be described as"high in the south and low in the north,"and significant differences in carbon emission performance were found between cities.The spatial Markov probabilistic transfer matrix results indicate that the transfer of carbon emission performance in Chinese cities is stable,resulting in a"club convergence"phenomenon.Furthermore,neighborhood backgrounds play an important role in the transfer between carbon emission performance types.Based on the prediction of long-term trends in carbon emission performance,carbon emission performance is expected to improve gradually over time.Therefore,China should continue to strengthen research and development aimed at improving urban carbon emission performance and achieving the national energy conservation and emission reduction goals.Meanwhile,neighboring cities with different neighborhood backgrounds should pursue cooperative economic strategies that balance economic growth,energy conservation,and emission reductions to realize low-carbon construction and sustainable development.展开更多
The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves...The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves the hardness, tensile strength and abrasion resistance of medium carbon and high C - low Cr steels. The results indicate that the material removal during abrasion is controlled by a number of factors, such as hardness, chemical composition, microstructure and heat treatment conditions. The conclusion is that the heat treated high C - low Cr steel and mild steel carburized by using coaltar pitch provide the best hardness and abrasion resistance and thus appear to be the most suitable materials for making agricultural tools.展开更多
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an...Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.展开更多
As pig production is a main contributor of greenhouse gas(GHG) emissions from livestock sector,the carbon emissions of pig production are attracting increasing attention,especially in the developing countries. Based o...As pig production is a main contributor of greenhouse gas(GHG) emissions from livestock sector,the carbon emissions of pig production are attracting increasing attention,especially in the developing countries. Based on the panel data of 30 provinces in China from 2001 to 2012,this paper measures the provincial carbon emission performance(CEP) of pig production and we use a Malmquist DEA approach to analyze the decomposition which includes desirable and undesirable output. Furthermore,the regional disparity in carbon emission performance of pig production is also analyzed and finally the convergence is tested. The main results are as follows:(i) there are provincial differences in carbon emission performance changing of pig production in China,and the carbon emission performance of pig production in 30 provinces has a downward trend during this period;(ii) among China’s three major economic regions,in terms of carbon emission performance of pig production,they are ranked in descending order as follows: Western China,Central China and Eastern China;(iii) convergence testing shows that there is a convergence trend for carbon emission performance both nationally and for the three regions.展开更多
We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of ...We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of the CNFET device and an overall chaotic circuit is pointed out. To verify the effect of temperature variation on the output dynamics of the chaotic circuit, a simulation is performed by employing the CNFET compact model of Wong et al. in HSPICE with a temperature range from -100℃ to 100℃. The obtained results with time series, frequency spectra, and bifurcation diagram from the simulation demonstrate that temperature plays a significant role in the output dynamics of the CNFET-based chaotic circuit. Thus, temperature-related issues should be taken into account while designing a high-quality chaotic generator with high stability.展开更多
In this work, a metal-organic framework derived nanoporous carbon （MOF-5-C） was fabricated and modified with Fe3O4 magnetic nanoparticles. The resulting magnetic MOF-5-derived porous carbon （Fe304@MOF-5-C） was the...In this work, a metal-organic framework derived nanoporous carbon （MOF-5-C） was fabricated and modified with Fe3O4 magnetic nanoparticles. The resulting magnetic MOF-5-derived porous carbon （Fe304@MOF-5-C） was then used for the magnetic solid-phase extraction of chlorophenols （CPs） from mushroom samples prior to high performance liquid chromatography-ultraviolet detection. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and N2 adsorption were used to characterize the adsorbent. After experimental optimization, the amount of the adsorbent was chosen as 8.0 mg, extraction time as 10 min, sample volume as 50 mL, desorption solvent as 0.4 mL （0.2 mL × 2） of alkaline methanol, and sample pH as 6. Under the above optimized conditions, good linearity for the analytes was obtained in the range of 0.8-100.0 ng g 1 with the correlation coefficients between 0.9923 and 0.9963. The limits of detection （SIN= 3） were in the range of 0.25-0.30 ng g-1, and the relative standard deviations were below 6.8%. The result showed that the Fe304@MOF-5-C has an excellent adsorption capacity for the analytes.展开更多
The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes ...The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes and zirconium diboride （ZrB2）, were used in a new design of mixture to produce the heat- resistant ablative composite system. The CNT/ZrB2/carbon/phenolic nanocomposite （Z/NT-CR） system corresponding to CNT/carbon/phenolic nanocomposite （NT-CR） showed a reasonable decrease in mass loss and the ablation rate as compared to carbon/phenolic composite （CR）. However, substantial drop in two factors was found for Z/NT-CR as compared to carbon/phenolic and NT-CR. Ablation mechanisms for all three composites were investigated by thermal gravimetric analysis in conjunction with micro- structural studies using a field emission scanning electron microscope. The microstructural studies revealed that CNTs acted as an ablation resistant phase for protection against 2000 ℃, and the conversion from ZrB2 to ZrO2 played an important role as an insulator in the performance of char layer in the ablation resistance.展开更多
An analysis of a booster arm made of a carbon fiber reinforced epoxy composite material is conducted by means of a finite element analysis method.The mechanical properties are also determined through stretching and co...An analysis of a booster arm made of a carbon fiber reinforced epoxy composite material is conducted by means of a finite element analysis method.The mechanical properties are also determined through stretching and compression performance tests.It is found that the surface treatment of the fibers causes the silane coupling agent to undergo a chemical reaction on the surface of the glass fiber.The used material succeeds in producing significant vibrations damping(vibration attenuation effect is superior to that obtained with conventional alloy materials).展开更多
Carbon nanotubes（CNTs） were deposited uniformly on carbon cloth by electrophoretic deposition（EPD）. Thereafter, CNT-doped clothes were stacked and densified by pyrocarbon via chemical vapor infiltration to fabrica...Carbon nanotubes（CNTs） were deposited uniformly on carbon cloth by electrophoretic deposition（EPD）. Thereafter, CNT-doped clothes were stacked and densified by pyrocarbon via chemical vapor infiltration to fabricate two-dimensional（2 D） carbon/carbon（C/C） composites. Effects of EPD CNTs on interlaminar shear performance and mode Ⅱ interlaminar fracture toughness（GⅡc） of 2 D C/C composites were investigated. Results showed that EPD CNTs were uniformly covered on carbon fibers, acting as a porous coating. Such a CNT coating can obviously enhance the interlaminar shear strength and GⅡc of 2 D C/C composites. With increaing EPD CNTs, the interlaminar shear strength and GⅡc of 2 D C/C composites increase greatly and then decrease, both of which run up to their maximum values, i e, 13.6 MPa and 436.0 J·m-2, when the content of EPD CNTs is 0.54 wt%, 2.27 and 1.45 times of the baseline. Such improvements in interlaminar performance of 2 D C/C composites are mainly beneficial from their increased cohesion of interlaminar matrix, which is caused not only by the direct reinforcing effect of EPD CNT network but also by the capacity of EPD CNTs to refine pyrocarbon matrix and induce multilayered microstructures that greatly increase the crack propagation resistance through ＂crack-blocking and-deflecting mechanisms＂.展开更多
Underground carbon sequestration(CS)by solid waste backfill(SWB)offers an effective pathway for collaborative disposal of coal-based solid waste and CO_(2),where the amount of carbon sequestration is an important eval...Underground carbon sequestration(CS)by solid waste backfill(SWB)offers an effective pathway for collaborative disposal of coal-based solid waste and CO_(2),where the amount of carbon sequestration is an important evaluation parameter.In this study,the concept of whole-process carbon sequestration using coal-based solid waste and CO_(2),including sequential stirring and curing stages,was proposed to evaluate the performance evolution of CS.The results showed that CO_(2) pressure and ambient temperature positively correlated with the CS amount from coal-based SWB.In particular,CO_(2) pressure prevailed in the stirring stage,while the ambient temperature effect was more significant in the curing stage.The CS amounts obtained during the stirring stage alone,the curing stage alone,and two sequential stages ranged from 0.66%–3.10%,3.53%–5.09%,and 5.12%–6.02%,respectively.The functional group and micromorphology analyses revealed that the prevailing mechanism at the CS stirring stage was the stirringdriven gas dissolution-leaching-mineralization reaction,while that at the curing stage was the hydration-driven gas permeation-dissociation-CS reaction.Both were essentially solid-liquid-gas multiphase chemical reactions.The results are instrumental in substantiating the coal-based SWB carbon sequestration evolution patterns and mechanisms and providing data support for waste disposal and carbon emission reduction in the coal industry.展开更多
To achieve carbon peak targets,realize carbon neutrality vision,and tackle global climate change,China must improve the carbon emission performance at the city level.Based on the carbon emission performance of 191 pre...To achieve carbon peak targets,realize carbon neutrality vision,and tackle global climate change,China must improve the carbon emission performance at the city level.Based on the carbon emission performance of 191 prefecture-level cities in China from 1997 to 2017,this paper analyses the evolution characteristics of urban carbon emission performance from three aspects:the overall spatial and temporal evolution,the differences according to both region and city size,and the differences among clusters categorized by carbon emission performance at the city level.This paper also reveals the impact of the social and economic transition on China’s carbon emission performance.The results show that:(1)The overall level of carbon emission performance of Chinese cities is low,and there is a downward trend during the study period.The differences in carbon emission performance among cities are convergent,but there is a wide gap between high and low values.(2)The carbon emission performance of cities in eastern coastal areas is higher than that in non-coastal areas cities.Large urban agglomerations and economically developed regions,such as provincial capitals,are the agglomeration areas of high urban carbon emission performance values.(3)The carbon emission performance level of cities with similar sizes will converge.At the same time,such changes will enhance the differences among carbon emission performances at the city level within the same region.(4)Cities that belong to high urban carbon emission performance clusters are mainly distributed in the eastern region.Such cities are classified into large cities,supercities,and megacities.Compared with low urban carbon emission performance clusters,cities in high urban carbon emission performance clusters show a higher proportion in the medium-high level and high level of carbon emission performance.Moreover,cities in high urban carbon emission performance clusters are more likely to improve their urban carbon emission performance.(5)The economic agglomeration effect,industrial structure adjustment and carbon intensity reduction have a significant impact on improving urban carbon emission performance.Population agglomeration has an incremental effect,and the anticipated benefits of environmental regulation have yet to be fully realized.The impacts of different clusters and different regions are variable.Finally,this paper advances policy enlightenment according to its research findings.展开更多
Efficient electrode material is crucial for energy conversion from renewable sources such as solar electricity. We present a method for preparation of carbon nanotubes （CNTs） with zeolitic imidazolate frameworks （Z...Efficient electrode material is crucial for energy conversion from renewable sources such as solar electricity. We present a method for preparation of carbon nanotubes （CNTs） with zeolitic imidazolate frameworks （ZIFs, e.g., ZIF-8） via an in situ pyrolysis process. The resultant materials are completely new carbon composites with desirable hierarchical porosity and nitrogen-doped features. Electron microscopy images show that CNTs with small external diameters enable more uniform dispersion of ZlF-8-derived carbons, subsequently yielding a unique hierarchically porous structure. Such carbon shows superior activity in oxygen reduction reaction （ORR） and high performance of supercapacitance, making it a valu- able metal-flee electrode material and a competent alternative to the state-of-the-art Pt/C catalyst. The electrocatalytic performance of CNTs can be dramatically improved by the incorporation of ZIF-8-derived carbons, which is attributed to the combination of good conductivity, abundant accessible dopant species, as well as proper porosity. Our method offers a new avenue for constructing electrocatalysts by effective integration of ZlF-8-derived carbon and the CNTs skeleton.展开更多
GeO2–C fibers were successfully synthesized using electrospinning homogeneous sol and subsequent calcination in an inert atmosphere. The spinnable sol was prepared by adding polyacrylonitrile（PAN）and polyvinylpyrro...GeO2–C fibers were successfully synthesized using electrospinning homogeneous sol and subsequent calcination in an inert atmosphere. The spinnable sol was prepared by adding polyacrylonitrile（PAN）and polyvinylpyrrolidone（PVP） in a weight ratio of 1：1 into a mixture with white precipitate produced by dropping GeCl4 into DMF. X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）,thermogravimetric analysis（TGA）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） were employed to characterize the as-obtained fibers, and electrochemical tests were conducted to measure electrochemical performance of the electrode. The electrospun fibers have uniform diameters of 300 nm. After being calcined at 600 8C for 2 h in Ar, they transform to amorphous GeO2–C fibers with the same morphologies. The Ge O2–C fibers exhibit excellent cycling stability with a high reversible capacity of 838.93 m A h g^-1after 100 cycles at a current density of 50 m A g^-1, indicating the composite fibers could be promising anode candidates for lithium-ion batteries.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.42101164)Major Project of Philosophy and Social Sciences in Colleges and Universities by Jiangsu Province(No.2024SJZD025)。
文摘Climate change caused by carbon emissions is a hot topic of concern.Enhancing carbon emission performance(CEP)emerges as a pivotal strategy to curtail carbon emissions,with the digital economy recognized as a crucial instrument for bolstering CEP.Grounded in theoretical analysis,this article takes the Yangtze River Delta region(YRD)as the research object and conducts empirical analysis for the period from 2010 to 2021.The Super Epsilon-Based Measure(EBM)model was employed to assess CEP,while the entropy method was used to quantify the level of the digital economy.Baseline regression models and mediation effect models were constructed to test the research hypotheses.Additionally,the Spatial Durbin Model(SDM)was utilized to analyze the spatial spillover effects of the digital economy.Some conclusions were drawn as follows.Firstly,both the digital economy and CEP exhibit growing trends and demonstrate significant spatial distribution characteristics.Cities with high CEP are increasingly concentrated along the Yangtze River and coastal areas.Meanwhile,the digital economy generally demonstrates a spatial distribution pattern of being higher in the southeast and lower in the northwest.Secondly,the digital economy exerts a notable and consistent positive influence on CEP,but this impact is not primarily achieved through promoting green technology innovation.Instead,the digital economy exhibits a stronger intermediary effect on CEP by facilitating industrial structure upgrading and rationalization.Thirdly,the digital economy significantly enhancing local CEP but having an insignificant impact on neighboring cities'CEP.To address these findings,cities ought to invest in digital infrastructure,incentivize digital innovation through policy and financial backing,and harness advanced technologies like 5G and blockchain to promote low-carbon,intelligent production and lifestyles,while enhancing industrial structure and regional cooperation to foster a low-carbon digital economy network.
基金This research was supported by the projects of the National Social Funds of China(Grant No.18BJY085)the Think Tank Special Project of Hunan Social Science(Grant No.18ZWB22)the Project of Social Science Achievement Evaluation Committee of Hunan Province.
文摘Carbon emission reduction is the only way to alleviate environmental problems,such as global warming.Effective evaluation of carbon performance can help enterprises to carry out energy saving and emission reduction activities to a certain extent and promote sustainable development.This paper constructs a carbon performance evaluation index system that includes the four dimensions of carbon resource(energy)input,cycle,output,and carbon management by incorporating the principles of circular economy and the theory of resource value circulation from the perspective of the flow trajectory of carbon-containing resources in the circulation of enterprises combined with the production characteristics of thermoelectric enterprises.Subsequently,combined with the case study,this paper discusses the scientific and practical nature of the system and provides another way of thinking for carbon performance evaluation of micro-enterprises in other industries.This paper expands the application boundary of matter-element model and supplements the literature of carbon performance,which has certain theoretical and practical significance.
文摘Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization’s carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.
基金supported by the National Natural Science Foundation of China(21473089,51232003,21373108,51571110,21573107)the Nation-al Basic Research Program of China(973 Program,2013CB932902)+2 种基金Suzhou Science and Technology Projects(ZXG2013025)Changzhou Science and Technology Projects(CE20130032)supported by a Project Funded by the Technology Support Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with 20 wt% loading has a homogeneous dispersion of Pt nanoparticles with the average size of 3.3 nm, which is smaller than 4.3 and 4.9 nm for the control catalysts with the same loading supported on hierarchical carbon nanocages （hCNC） and commercial Vulcan XC-72, respec- tively. Accordingly, Pt/hNCNC has a larger electrochemical surface area than Pt/hCNC and Pt/XC-72. The Pt/hNCNC catalyst exhibited excellent electrocatalytic activity and stability for methanol oxidation, which was better than the control catalysts. This was attributed to the en- hanced interaction between Pt and hNCNC due to nitrogen participation in the anchoring function. By making use of the unique advantages of the hNCNC support, a heavy Pt loading up to 60 wt% was prepared without serious agglomeration, which gave a high peak-current density per unit mass of catalyst of 95.6 mA/mg for achieving a high power density. These results showed the potential of the Pt/hNCNC catalyst for methanol oxidation and of the new hNCNC support for wide applications.
文摘Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization's carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.
基金Fundamental Research Funds for the Central UniversitiesNo.19lgzd09+2 种基金Guangdong Special Support ProgramPearl River S&T Nova Program of GuangzhouNo.201806010187
文摘Climate change resulting from CO_2 emissions has become an important global environmental issue in recent years.Improving carbon emission performance is one way to reduce carbon emissions.Although carbon emission performance has been discussed at the national and industrial levels,city-level studies are lacking due to the limited availability of statistics on energy consumption.In this study,based on city-level remote sensing data on carbon emissions in China from 1992–2013,we used the slacks-based measure of super-efficiency to evaluate urban carbon emission performance.The traditional Markov probability transfer matrix and spatial Markov probability transfer matrix were constructed to explore the spatiotemporal evolution of urban carbon emission performance in China for the first time and predict long-term trends in carbon emission performance.The results show that urban carbon emission performance in China steadily increased during the study period with some fluctuations.However,the overall level of carbon emission performance remains low,indicating great potential for improvements in energy conservation and emission reduction.The spatial pattern of urban carbon emission performance in China can be described as"high in the south and low in the north,"and significant differences in carbon emission performance were found between cities.The spatial Markov probabilistic transfer matrix results indicate that the transfer of carbon emission performance in Chinese cities is stable,resulting in a"club convergence"phenomenon.Furthermore,neighborhood backgrounds play an important role in the transfer between carbon emission performance types.Based on the prediction of long-term trends in carbon emission performance,carbon emission performance is expected to improve gradually over time.Therefore,China should continue to strengthen research and development aimed at improving urban carbon emission performance and achieving the national energy conservation and emission reduction goals.Meanwhile,neighboring cities with different neighborhood backgrounds should pursue cooperative economic strategies that balance economic growth,energy conservation,and emission reductions to realize low-carbon construction and sustainable development.
文摘The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves the hardness, tensile strength and abrasion resistance of medium carbon and high C - low Cr steels. The results indicate that the material removal during abrasion is controlled by a number of factors, such as hardness, chemical composition, microstructure and heat treatment conditions. The conclusion is that the heat treated high C - low Cr steel and mild steel carburized by using coaltar pitch provide the best hardness and abrasion resistance and thus appear to be the most suitable materials for making agricultural tools.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,51372269,and 51472264)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.
基金Supported by National Natural Science Foundation of China(41171436)National Social Science Foundation of China(14AZD002)
文摘As pig production is a main contributor of greenhouse gas(GHG) emissions from livestock sector,the carbon emissions of pig production are attracting increasing attention,especially in the developing countries. Based on the panel data of 30 provinces in China from 2001 to 2012,this paper measures the provincial carbon emission performance(CEP) of pig production and we use a Malmquist DEA approach to analyze the decomposition which includes desirable and undesirable output. Furthermore,the regional disparity in carbon emission performance of pig production is also analyzed and finally the convergence is tested. The main results are as follows:(i) there are provincial differences in carbon emission performance changing of pig production in China,and the carbon emission performance of pig production in 30 provinces has a downward trend during this period;(ii) among China’s three major economic regions,in terms of carbon emission performance of pig production,they are ranked in descending order as follows: Western China,Central China and Eastern China;(iii) convergence testing shows that there is a convergence trend for carbon emission performance both nationally and for the three regions.
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea Funded by the Ministry of Education,Science and Technology under Grant No 2012-0002777
文摘We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of the CNFET device and an overall chaotic circuit is pointed out. To verify the effect of temperature variation on the output dynamics of the chaotic circuit, a simulation is performed by employing the CNFET compact model of Wong et al. in HSPICE with a temperature range from -100℃ to 100℃. The obtained results with time series, frequency spectra, and bifurcation diagram from the simulation demonstrate that temperature plays a significant role in the output dynamics of the CNFET-based chaotic circuit. Thus, temperature-related issues should be taken into account while designing a high-quality chaotic generator with high stability.
基金Financial support from the National Natural Science Foundation of China (Nos. 31471643, 31571925)the Innovation Research Program of the Department of Education of Hebei for Hebei Provincial Universities (No. LJRC009)
文摘In this work, a metal-organic framework derived nanoporous carbon （MOF-5-C） was fabricated and modified with Fe3O4 magnetic nanoparticles. The resulting magnetic MOF-5-derived porous carbon （Fe304@MOF-5-C） was then used for the magnetic solid-phase extraction of chlorophenols （CPs） from mushroom samples prior to high performance liquid chromatography-ultraviolet detection. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and N2 adsorption were used to characterize the adsorbent. After experimental optimization, the amount of the adsorbent was chosen as 8.0 mg, extraction time as 10 min, sample volume as 50 mL, desorption solvent as 0.4 mL （0.2 mL × 2） of alkaline methanol, and sample pH as 6. Under the above optimized conditions, good linearity for the analytes was obtained in the range of 0.8-100.0 ng g 1 with the correlation coefficients between 0.9923 and 0.9963. The limits of detection （SIN= 3） were in the range of 0.25-0.30 ng g-1, and the relative standard deviations were below 6.8%. The result showed that the Fe304@MOF-5-C has an excellent adsorption capacity for the analytes.
文摘The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes and zirconium diboride （ZrB2）, were used in a new design of mixture to produce the heat- resistant ablative composite system. The CNT/ZrB2/carbon/phenolic nanocomposite （Z/NT-CR） system corresponding to CNT/carbon/phenolic nanocomposite （NT-CR） showed a reasonable decrease in mass loss and the ablation rate as compared to carbon/phenolic composite （CR）. However, substantial drop in two factors was found for Z/NT-CR as compared to carbon/phenolic and NT-CR. Ablation mechanisms for all three composites were investigated by thermal gravimetric analysis in conjunction with micro- structural studies using a field emission scanning electron microscope. The microstructural studies revealed that CNTs acted as an ablation resistant phase for protection against 2000 ℃, and the conversion from ZrB2 to ZrO2 played an important role as an insulator in the performance of char layer in the ablation resistance.
基金financially supported by Scientific Research Fund of Yunnan Institute of Engineering(2019gchy01).
文摘An analysis of a booster arm made of a carbon fiber reinforced epoxy composite material is conducted by means of a finite element analysis method.The mechanical properties are also determined through stretching and compression performance tests.It is found that the surface treatment of the fibers causes the silane coupling agent to undergo a chemical reaction on the surface of the glass fiber.The used material succeeds in producing significant vibrations damping(vibration attenuation effect is superior to that obtained with conventional alloy materials).
基金Funded by the National Natural Science Foundation of China(Nos.51432008,51202194 and 51502242)the Fund of the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP201637)the Key Grant Project of the Chinese Ministry of Education(No.313047)
文摘Carbon nanotubes（CNTs） were deposited uniformly on carbon cloth by electrophoretic deposition（EPD）. Thereafter, CNT-doped clothes were stacked and densified by pyrocarbon via chemical vapor infiltration to fabricate two-dimensional（2 D） carbon/carbon（C/C） composites. Effects of EPD CNTs on interlaminar shear performance and mode Ⅱ interlaminar fracture toughness（GⅡc） of 2 D C/C composites were investigated. Results showed that EPD CNTs were uniformly covered on carbon fibers, acting as a porous coating. Such a CNT coating can obviously enhance the interlaminar shear strength and GⅡc of 2 D C/C composites. With increaing EPD CNTs, the interlaminar shear strength and GⅡc of 2 D C/C composites increase greatly and then decrease, both of which run up to their maximum values, i e, 13.6 MPa and 436.0 J·m-2, when the content of EPD CNTs is 0.54 wt%, 2.27 and 1.45 times of the baseline. Such improvements in interlaminar performance of 2 D C/C composites are mainly beneficial from their increased cohesion of interlaminar matrix, which is caused not only by the direct reinforcing effect of EPD CNT network but also by the capacity of EPD CNTs to refine pyrocarbon matrix and induce multilayered microstructures that greatly increase the crack propagation resistance through ＂crack-blocking and-deflecting mechanisms＂.
基金supported by the National Key R&D Program of China(No.2023YFC3904304)the National Natural Science Foundation of China(No.52304158)Jiangsu Key Laboratory for Clean Utilization of Carbon Resources Research Project(No.BM2024007)。
文摘Underground carbon sequestration(CS)by solid waste backfill(SWB)offers an effective pathway for collaborative disposal of coal-based solid waste and CO_(2),where the amount of carbon sequestration is an important evaluation parameter.In this study,the concept of whole-process carbon sequestration using coal-based solid waste and CO_(2),including sequential stirring and curing stages,was proposed to evaluate the performance evolution of CS.The results showed that CO_(2) pressure and ambient temperature positively correlated with the CS amount from coal-based SWB.In particular,CO_(2) pressure prevailed in the stirring stage,while the ambient temperature effect was more significant in the curing stage.The CS amounts obtained during the stirring stage alone,the curing stage alone,and two sequential stages ranged from 0.66%–3.10%,3.53%–5.09%,and 5.12%–6.02%,respectively.The functional group and micromorphology analyses revealed that the prevailing mechanism at the CS stirring stage was the stirringdriven gas dissolution-leaching-mineralization reaction,while that at the curing stage was the hydration-driven gas permeation-dissociation-CS reaction.Both were essentially solid-liquid-gas multiphase chemical reactions.The results are instrumental in substantiating the coal-based SWB carbon sequestration evolution patterns and mechanisms and providing data support for waste disposal and carbon emission reduction in the coal industry.
基金supported by the Ministry of Education Research in the Humanities and Social Sciences Planning Fund(Grant No.21YJAZH087)the National Natural Science Foundation of China Innovation Research Group Project(Grant No.42121001)。
文摘To achieve carbon peak targets,realize carbon neutrality vision,and tackle global climate change,China must improve the carbon emission performance at the city level.Based on the carbon emission performance of 191 prefecture-level cities in China from 1997 to 2017,this paper analyses the evolution characteristics of urban carbon emission performance from three aspects:the overall spatial and temporal evolution,the differences according to both region and city size,and the differences among clusters categorized by carbon emission performance at the city level.This paper also reveals the impact of the social and economic transition on China’s carbon emission performance.The results show that:(1)The overall level of carbon emission performance of Chinese cities is low,and there is a downward trend during the study period.The differences in carbon emission performance among cities are convergent,but there is a wide gap between high and low values.(2)The carbon emission performance of cities in eastern coastal areas is higher than that in non-coastal areas cities.Large urban agglomerations and economically developed regions,such as provincial capitals,are the agglomeration areas of high urban carbon emission performance values.(3)The carbon emission performance level of cities with similar sizes will converge.At the same time,such changes will enhance the differences among carbon emission performances at the city level within the same region.(4)Cities that belong to high urban carbon emission performance clusters are mainly distributed in the eastern region.Such cities are classified into large cities,supercities,and megacities.Compared with low urban carbon emission performance clusters,cities in high urban carbon emission performance clusters show a higher proportion in the medium-high level and high level of carbon emission performance.Moreover,cities in high urban carbon emission performance clusters are more likely to improve their urban carbon emission performance.(5)The economic agglomeration effect,industrial structure adjustment and carbon intensity reduction have a significant impact on improving urban carbon emission performance.Population agglomeration has an incremental effect,and the anticipated benefits of environmental regulation have yet to be fully realized.The impacts of different clusters and different regions are variable.Finally,this paper advances policy enlightenment according to its research findings.
基金supported by the Award Program for Fujian Minjiang Scholar Professorshipthe National Natural Science Foundation of China (21571035)
文摘Efficient electrode material is crucial for energy conversion from renewable sources such as solar electricity. We present a method for preparation of carbon nanotubes （CNTs） with zeolitic imidazolate frameworks （ZIFs, e.g., ZIF-8） via an in situ pyrolysis process. The resultant materials are completely new carbon composites with desirable hierarchical porosity and nitrogen-doped features. Electron microscopy images show that CNTs with small external diameters enable more uniform dispersion of ZlF-8-derived carbons, subsequently yielding a unique hierarchically porous structure. Such carbon shows superior activity in oxygen reduction reaction （ORR） and high performance of supercapacitance, making it a valu- able metal-flee electrode material and a competent alternative to the state-of-the-art Pt/C catalyst. The electrocatalytic performance of CNTs can be dramatically improved by the incorporation of ZIF-8-derived carbons, which is attributed to the combination of good conductivity, abundant accessible dopant species, as well as proper porosity. Our method offers a new avenue for constructing electrocatalysts by effective integration of ZlF-8-derived carbon and the CNTs skeleton.
基金supported by Shanghai Municipal Education Commission(High-energy Beam Intelligent Processing and Green Manufacturing)and Graduate Students Innovation Program of Shanghai University of Engineering Science(No.E1-0903-15-01040)
文摘GeO2–C fibers were successfully synthesized using electrospinning homogeneous sol and subsequent calcination in an inert atmosphere. The spinnable sol was prepared by adding polyacrylonitrile（PAN）and polyvinylpyrrolidone（PVP） in a weight ratio of 1：1 into a mixture with white precipitate produced by dropping GeCl4 into DMF. X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）,thermogravimetric analysis（TGA）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） were employed to characterize the as-obtained fibers, and electrochemical tests were conducted to measure electrochemical performance of the electrode. The electrospun fibers have uniform diameters of 300 nm. After being calcined at 600 8C for 2 h in Ar, they transform to amorphous GeO2–C fibers with the same morphologies. The Ge O2–C fibers exhibit excellent cycling stability with a high reversible capacity of 838.93 m A h g^-1after 100 cycles at a current density of 50 m A g^-1, indicating the composite fibers could be promising anode candidates for lithium-ion batteries.
