The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of C...The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of CoSb_(3) materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases,nanointerfaces or nanopores, which greatly improves their ZT values. The phonon engineering can optimize significantly the thermal transport properties of CoSb_(3)-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb_(3)-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb_(3)-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb_(3) materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve performance of thermoelectric materials and provide new research ideas of development of high-efficiency thermoelectric materials.展开更多
The enhancements in thermoelectric(TE)performances of p-type skutterudites are usually limited due to the relatively low Seebeck coefficients owing to the higher carrier concentration and more impurity phases induced ...The enhancements in thermoelectric(TE)performances of p-type skutterudites are usually limited due to the relatively low Seebeck coefficients owing to the higher carrier concentration and more impurity phases induced by inherent structural instability of a Fe-based skutterudite.As shown in this study,alloying engineering of Ni doping at Fe sites in a p-type CeFe_(3.8)Co_(0.2)Sb_(12)skutterudite can not only reduce the impurity phases with high thermal conductivity but also regulate the carrier concentration,and thus significantly increase the Seebeck coefficient.The thermal conductivity was largely suppressed due to the enhanced point defect phonon scattering and decreased hole concentration.As a result,a TE figure of merit ZT of the CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)sample reached 0.8,which is approximately 50%higher than that of a Ni-free sample.Appropriate Ni doping can maintain a high ZT at a high temperature by controlling the reduction in a band gap.Therefore,a high average ZT close to 0.8 at 650–800 K for CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)was obtained,which was comparable to or even higher than those of the reported Ce-filled Fe-based skutterudites due to the synergistic optimization of electrical and thermal performances.This study provides a strategy to synergistically optimize electrical–thermal performances of the p-type skutterudites by alloying engineering.展开更多
Phase change materials are potential candidates for the application of latent heat storage.Herein,we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex,which were first p...Phase change materials are potential candidates for the application of latent heat storage.Herein,we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex,which were first prepared using cellulose 6-(N-pyridinium)hexanoyl ester as the cationic polyelectrolyte and carboxymethyl cellulose as the anionic polyelectrolyte to encapsulate polyethylene glycol by the vacuum impregnation method.Furthermore,the multi-walled carbon nanotube or graphene oxide,which were separately composited into the polyelectrolytes complex capsules to enhance thermal conductivity and light-to-thermal conversion efficiency.These capsules owned a typical core–shell structure,with an extremely high polyethylene glycol loading up to 34.33 g∙g^(‒1).After loading of polyethylene glycol,the resulted cellulose-based composite phase change materials exhibited high thermal energy storage ability with the latent heat up to 142.2 J∙g^(‒1),which was 98.5%of pure polyethylene glycol.Further results showed that the composite phase change materials demonstrated good form-stable property and thermal stability.Moreover,studies involving light-to-thermal conversion determined that composite phase change materials exhibited outstanding light-to-thermal conversion performance.Considering their exceptional comprehensive features,innovative composite phase change materials generated from cellulose presented a highly interesting choice for thermal management and renewable thermal energy storage.展开更多
Filled skutterudite is currently one of the most promising intermediate-temperature thermoelectric(TE)materials,having good thermoelectric transport performance and excellent mechanical properties.For the preparation ...Filled skutterudite is currently one of the most promising intermediate-temperature thermoelectric(TE)materials,having good thermoelectric transport performance and excellent mechanical properties.For the preparation of high-efficiency filled skutterudite TE devices,it is important to have p-and n-type filled skutterudite TE materials with matching performance.However,the current TE properties of p-type Fe-based filled skutterudite materials are worse than n-type filled skutterudite materials.Therefore,how to obtain high-performance p-type Fe-based filled skutterudite materials is the key to preparation of high-efficiency skutterudite-based TE devices.This review summarizes some methods for optimizing the thermal transport performance of p-type filled skutterudite materials at the atomic-molecular and nano-mesoscopic scale that have been used in recent years.These methods include doping,multi-atom filling,and use of low-dimensional structure and of nanocomposite.In addition,the synergistic optimization methods of the electrical and thermal transport parameters and advanced preparation technologies of p-type filled skutterudite materials in recent years are also briefly summarized.These optimizational methods and advanced preparation technologies can significantly improve the TE properties of p-type Fe-based filled skutterudite materials.展开更多
Heavy metal pollution is a major issue after tailing pond failure accident.It is important to predict pollution trends for limited data of pollution sources.A simple phase separation heavy metal model was built for ea...Heavy metal pollution is a major issue after tailing pond failure accident.It is important to predict pollution trends for limited data of pollution sources.A simple phase separation heavy metal model was built for early warning simulation of heavy metal pollution accidents.Based on this,a new simulation framework has been developed to predict the pollution trends of the downstream according to the measured data at upstream sections.By setting the upstream monitoring date as the inflow boundary condition,the changing processes of heavy metal manganese(Mn) with different phases in the downstream can be accurately simulated and forecasted.Results showed that the concentration of the suspended phase in the downstream was larger than that in the aqueous phase and sediment phase.With this,the early warning of pollution trends after accidents could be made a few days ahead.It indicates that the impact of sediment on heavy metal should not be ignored in the early warning of tailing pond failure accidents.展开更多
China’s reform and opening up policy initiated by the then leader Deng Xiaoping have undergone a 40-year process since 1978.This period was marked by one of the greatest economic reforms in modern history.In this stu...China’s reform and opening up policy initiated by the then leader Deng Xiaoping have undergone a 40-year process since 1978.This period was marked by one of the greatest economic reforms in modern history.In this study,we extract literature focused on the Chinese marketization context and marketing practices published in top-tier international marketing journals and Chinese management journals between 1978 and 2018.This study identifies the research questions and research domains investigated in our selected literature.The authors hope to reveal the general landscape and evolution made in the context of this unique period in Chinese history.This thematically focused literature review provides marketing scholars with a snapshot of the academic marketing research in China and gives rise to novel research directions related to the deepening of the economic reform.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 51872006)the Excellent Youth Project of Natural Science Foundation of Anhui Province of China (Grant No. 2208085Y17)。
文摘The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of CoSb_(3) materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases,nanointerfaces or nanopores, which greatly improves their ZT values. The phonon engineering can optimize significantly the thermal transport properties of CoSb_(3)-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb_(3)-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb_(3)-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb_(3) materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve performance of thermoelectric materials and provide new research ideas of development of high-efficiency thermoelectric materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.51872006,and 22273081)and Anhui Province Natural Science Foundation for Excellent Youth Scholars(Grant No.2208085Y17).
文摘The enhancements in thermoelectric(TE)performances of p-type skutterudites are usually limited due to the relatively low Seebeck coefficients owing to the higher carrier concentration and more impurity phases induced by inherent structural instability of a Fe-based skutterudite.As shown in this study,alloying engineering of Ni doping at Fe sites in a p-type CeFe_(3.8)Co_(0.2)Sb_(12)skutterudite can not only reduce the impurity phases with high thermal conductivity but also regulate the carrier concentration,and thus significantly increase the Seebeck coefficient.The thermal conductivity was largely suppressed due to the enhanced point defect phonon scattering and decreased hole concentration.As a result,a TE figure of merit ZT of the CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)sample reached 0.8,which is approximately 50%higher than that of a Ni-free sample.Appropriate Ni doping can maintain a high ZT at a high temperature by controlling the reduction in a band gap.Therefore,a high average ZT close to 0.8 at 650–800 K for CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)was obtained,which was comparable to or even higher than those of the reported Ce-filled Fe-based skutterudites due to the synergistic optimization of electrical and thermal performances.This study provides a strategy to synergistically optimize electrical–thermal performances of the p-type skutterudites by alloying engineering.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.31890774 and 31890770)the Fundamental Research Funds for the Central Universities(Grant No.2572018AB40)the National Training Program of Innovation and Entrepreneurship for Undergraduates of Northeast Forestry University(Grant No.202110225432).
文摘Phase change materials are potential candidates for the application of latent heat storage.Herein,we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex,which were first prepared using cellulose 6-(N-pyridinium)hexanoyl ester as the cationic polyelectrolyte and carboxymethyl cellulose as the anionic polyelectrolyte to encapsulate polyethylene glycol by the vacuum impregnation method.Furthermore,the multi-walled carbon nanotube or graphene oxide,which were separately composited into the polyelectrolytes complex capsules to enhance thermal conductivity and light-to-thermal conversion efficiency.These capsules owned a typical core–shell structure,with an extremely high polyethylene glycol loading up to 34.33 g∙g^(‒1).After loading of polyethylene glycol,the resulted cellulose-based composite phase change materials exhibited high thermal energy storage ability with the latent heat up to 142.2 J∙g^(‒1),which was 98.5%of pure polyethylene glycol.Further results showed that the composite phase change materials demonstrated good form-stable property and thermal stability.Moreover,studies involving light-to-thermal conversion determined that composite phase change materials exhibited outstanding light-to-thermal conversion performance.Considering their exceptional comprehensive features,innovative composite phase change materials generated from cellulose presented a highly interesting choice for thermal management and renewable thermal energy storage.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51872006)the Anhui University of Technology High-Level Doctoral Student Training Program(DT17200008).
文摘Filled skutterudite is currently one of the most promising intermediate-temperature thermoelectric(TE)materials,having good thermoelectric transport performance and excellent mechanical properties.For the preparation of high-efficiency filled skutterudite TE devices,it is important to have p-and n-type filled skutterudite TE materials with matching performance.However,the current TE properties of p-type Fe-based filled skutterudite materials are worse than n-type filled skutterudite materials.Therefore,how to obtain high-performance p-type Fe-based filled skutterudite materials is the key to preparation of high-efficiency skutterudite-based TE devices.This review summarizes some methods for optimizing the thermal transport performance of p-type filled skutterudite materials at the atomic-molecular and nano-mesoscopic scale that have been used in recent years.These methods include doping,multi-atom filling,and use of low-dimensional structure and of nanocomposite.In addition,the synergistic optimization methods of the electrical and thermal transport parameters and advanced preparation technologies of p-type filled skutterudite materials in recent years are also briefly summarized.These optimizational methods and advanced preparation technologies can significantly improve the TE properties of p-type Fe-based filled skutterudite materials.
基金supported by the National Nature Science Foundation of China (No.41807471)the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan)(Nos.G1323519399 and 162301182698)。
文摘Heavy metal pollution is a major issue after tailing pond failure accident.It is important to predict pollution trends for limited data of pollution sources.A simple phase separation heavy metal model was built for early warning simulation of heavy metal pollution accidents.Based on this,a new simulation framework has been developed to predict the pollution trends of the downstream according to the measured data at upstream sections.By setting the upstream monitoring date as the inflow boundary condition,the changing processes of heavy metal manganese(Mn) with different phases in the downstream can be accurately simulated and forecasted.Results showed that the concentration of the suspended phase in the downstream was larger than that in the aqueous phase and sediment phase.With this,the early warning of pollution trends after accidents could be made a few days ahead.It indicates that the impact of sediment on heavy metal should not be ignored in the early warning of tailing pond failure accidents.
基金This paper was originally funded by the authors themselves。
文摘China’s reform and opening up policy initiated by the then leader Deng Xiaoping have undergone a 40-year process since 1978.This period was marked by one of the greatest economic reforms in modern history.In this study,we extract literature focused on the Chinese marketization context and marketing practices published in top-tier international marketing journals and Chinese management journals between 1978 and 2018.This study identifies the research questions and research domains investigated in our selected literature.The authors hope to reveal the general landscape and evolution made in the context of this unique period in Chinese history.This thematically focused literature review provides marketing scholars with a snapshot of the academic marketing research in China and gives rise to novel research directions related to the deepening of the economic reform.