A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibi...A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.展开更多
Taking experimental path on disordering AuCuI（AAuCu8A4）composed of A Au8 and ACu4 stem alloy genes as an example, three discoveries and a method were presented. The ability of Au Cu I（AAu Cu8 A4）to keep structure ...Taking experimental path on disordering AuCuI（AAuCu8A4）composed of A Au8 and ACu4 stem alloy genes as an example, three discoveries and a method were presented. The ability of Au Cu I（AAu Cu8 A4）to keep structure stabilization against changing temperature is attributed to the fact that the AAu8 and ACu4 potential well depths greatly surpass their vibration energies, which leads to the subequilibrium of experimental path. A new atom movement mechanism of AuCuI（AAuACu84）to change structure for suiting variation in temperature is the resonance activating-synchro alternating of alloy genes, which leads to heterogeneous and successive subequilibrium transitions. There exists jumping order degree, which leads to the existence of jumping Tj-temperature and an unexpected so-called ＂retro-effect＂ about jumping temperature retrograde shift to lower temperatures upon the increasing heating rate. A set of subequilibrium holographic network path charts were obtained by the experimental mixed enthalpy path method.展开更多
Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic...Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con- ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction nilnt nlant studies.展开更多
The effects of Mo addition on microstructures,phase relationships,order–disorder phase-transition temperatures and room-temperature mechanical properties of Fe50Al50-nMon alloys(n=1,3,5,7,and 9,mole fraction,%)were i...The effects of Mo addition on microstructures,phase relationships,order–disorder phase-transition temperatures and room-temperature mechanical properties of Fe50Al50-nMon alloys(n=1,3,5,7,and 9,mole fraction,%)were investigated after solidification and heat treatment.Structural characterization of the samples was performed via X-ray diffraction(XRD),scanning electron microscopy(SEM)and differential scanning calorimetry.Room-temperature mechanical properties were investigated by conducting compression and microhardness tests.Mo3Al particles precipitated in all alloys because of the limited solid solubility of Mo in the Fe-Al-based phases.The as-cast Fe50Al50-nMon alloys exhibited brittle behavior with high yield strength and limited fracture strain at room temperature.Compared with the as-cast alloys,all the heat-treated alloys except for the Fe50Al41Mo9 alloy exhibited enhanced mechanical properties at room temperature.The heat-treated Fe50Al43Mo7 alloy exhibited the highest fracture strain and compressive strength of 25.4%and 2.3 GPa,respectively.展开更多
The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into differ...The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.展开更多
In this paper, taking Nb-Mo alloy system as an example, the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the ...In this paper, taking Nb-Mo alloy system as an example, the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the number of coordination atoms. The concentrations of characteristic atoms in B2-NbMo type ordered alloys were calculated as functions of ordering degree（s） and composition Xuo. When S=Smax, the concentrations of characteristic atoms of stoichiometric B2-NbMo intermetallic compound are equal to that of alloys, that is, X8^Nb = 0.5 at, X0^Mo= 0.5 at. As ordering degree decreases, characteristic atoms A8^Nb and A0^Mo of B2-NbMo type ordered alloy split. And the degree of splitting of characteristic atoms increases with the ordering degree decreasing. Therefore, disordered alloys and various types of ordered alloys can be designed.展开更多
Organic quinone compounds have attracted wide attention due to their high theoretical capacities.Here,a novel cyclic macromolecular calix[6]quinone(C6Q),which possesses 6 p-quinone units and can provide 12 electrochem...Organic quinone compounds have attracted wide attention due to their high theoretical capacities.Here,a novel cyclic macromolecular calix[6]quinone(C6Q),which possesses 6 p-quinone units and can provide 12 electrochemical active sites,has been applied as a promising cathode material in lithium ion batteries(LIBs).The as-fabricated LIBs exhibited an initial specific capacity as high as 423 mA h g^-1(Ctheo=447 mA h g^-1)at 0.1 C.After 100 cycles,the capacity of C6Q maintained at 216 mA h g^-1,and even after 300 cycles,C6Q still achieved a high specific capacity of 195 mA h g^-1 with negligible capacity fading(as compared with the 100th cycle).Due to the large capacity and wide electrochemical window,C6Q can deliver a specific energy up to 1201 W h kg^-1.In addition,the method of immobilizing C6Q with ordered mesoporous carbon(OMC)CMK-3 could further enhance the electrochemical performance of C6Q.展开更多
Ordered mesoporous Cu-Mg-A1 composite oxides were synthesized via the one-pot evaporation-in- duced self-assembly strategy. Using this method, copper was first homogeneously incorporated into the ordered mesoporous sp...Ordered mesoporous Cu-Mg-A1 composite oxides were synthesized via the one-pot evaporation-in- duced self-assembly strategy. Using this method, copper was first homogeneously incorporated into the ordered mesoporous spinel matrix. After H2 reduction treatment, according to X-ray diffraction （XRD） and transmission electron microscopy （TEM） results, copper existed as metallic nanoparticles with the size of 6-10 nm that well decorated the parent mesoporous skeleton. The metallic nanoparticles were then re-oxidized to copper oxide when exposed to air or during CO oxidation reaction at low temperatures. Thus, copper migrated from bulk spinel phase to the surface after the reduction-oxidation treat- ment. Moreover, the copper on the surface was re-incor- porated into the bulk spinel phase by further thermal treatment at much higher temperature in the presence of air. The correlation between the state of copper in the mesoporous composite oxides and the catalytic perfor- mance toward CO oxidation was studied. It was found that copper existed as oxide nanoparticles on the surface of mesoporous Mg-Al skeleton is much more active than that existed as lattice Cu ions in spinel phase.展开更多
文摘利用第一性原理模拟计算铜铟硒(CIS)太阳能电池CIS吸收层,及CIS中普遍存在的有序缺陷化合物(ordered defect compound,ODC)CuIn_5Se_8的性质.依据CuIn_5Se_8形成的方式,结合对称性越高、能量越低的原则,建立CuInS_2中的ODC-CuIn_5S_8结构,并从态密度角度讨论CuInS2与CuIn_5S_8的差异.分别选用ZnSe和CuI半导体作为CIS和CuInS_2电池的缓冲层,利用第一性原理计算得到价带偏移(valence band offset,VBO).在ZnSe/CIS界面处,CIS的价带顶(valence band maximum,VBM)比ZnSe高0.52 eV;在CuI/CuInS_2界面处,CuI的价带顶比CuInS_2低0.37 eV,表明CuI非常适合应用于CuInS_2电池缓冲层.ODC中由于Cu的缺失,其d轨道电子和阴离子p轨道电子的p-d排斥力减小,使ODC材料的价带顶相对于自身本征材料有所下降.
基金supported by the National Natural Science Foundation of China(21177160,21303263,21477164)Beijing Nova Program(Z141109001814072)+1 种基金Specialized Research Fund for the Doctoral Program of High Education of China(20130007120011)the Science Foundation of China University of Petroleum-Beijing(2462013YJRC13,2462013BJRC003)~~
文摘A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.
基金Project(51071181)supported by the National Natural Science Foundation of ChinaProject(2013FJ4043)supported by the Natural Science Foundation of Hunan Province,China
文摘Taking experimental path on disordering AuCuI（AAuCu8A4）composed of A Au8 and ACu4 stem alloy genes as an example, three discoveries and a method were presented. The ability of Au Cu I（AAu Cu8 A4）to keep structure stabilization against changing temperature is attributed to the fact that the AAu8 and ACu4 potential well depths greatly surpass their vibration energies, which leads to the subequilibrium of experimental path. A new atom movement mechanism of AuCuI（AAuACu84）to change structure for suiting variation in temperature is the resonance activating-synchro alternating of alloy genes, which leads to heterogeneous and successive subequilibrium transitions. There exists jumping order degree, which leads to the existence of jumping Tj-temperature and an unexpected so-called ＂retro-effect＂ about jumping temperature retrograde shift to lower temperatures upon the increasing heating rate. A set of subequilibrium holographic network path charts were obtained by the experimental mixed enthalpy path method.
基金Support from the Australian Research Council (project ID:LP140100650)
文摘Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con- ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction nilnt nlant studies.
基金OYP Program at Middle East Technical University and The Scientific and Technological Research Council of Turkey,TUBITAKNational Scholarship Programme for PhD Students
文摘The effects of Mo addition on microstructures,phase relationships,order–disorder phase-transition temperatures and room-temperature mechanical properties of Fe50Al50-nMon alloys(n=1,3,5,7,and 9,mole fraction,%)were investigated after solidification and heat treatment.Structural characterization of the samples was performed via X-ray diffraction(XRD),scanning electron microscopy(SEM)and differential scanning calorimetry.Room-temperature mechanical properties were investigated by conducting compression and microhardness tests.Mo3Al particles precipitated in all alloys because of the limited solid solubility of Mo in the Fe-Al-based phases.The as-cast Fe50Al50-nMon alloys exhibited brittle behavior with high yield strength and limited fracture strain at room temperature.Compared with the as-cast alloys,all the heat-treated alloys except for the Fe50Al41Mo9 alloy exhibited enhanced mechanical properties at room temperature.The heat-treated Fe50Al43Mo7 alloy exhibited the highest fracture strain and compressive strength of 25.4%and 2.3 GPa,respectively.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11074293,51021061 and 50831006)
文摘The coexistence of magnetic ordering and ferroelectricity, ing on the origin of ferroelectricity, multiferroic materials known as multiferroics, has drawn a lot of research effort. Depend can be classified into different groups. In this paper, we review re cent progress in the field of multiferroics induced by different forms of charge ordering. In addition to a general description of charge order and electronic ferroelectricity, we focus on two specific systems： （1） charge order with frustration in RFe2O4 （R=Lu, Yb） system; （2） charge ordered perovskite manganites of the type （R1-xCax）MnO3 （R=La, Pr）. The charge ordering can be tuned by external electric fields, which results in pronounced magnetoelectric effects and strong dielectric tunability. Other materials and possible candidates with charge order induced multiferroics are also briefly summarized.
基金supported by the National Natural Science Foundation of China(Grant No.50954006)Hunan Science and Technology Department (Grant No.2009GK3152)+1 种基金Hunan Provincial Construction Department (Grant No.201012)Hunan Provincial Education Department(Grant No.21KZ)
文摘In this paper, taking Nb-Mo alloy system as an example, the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the number of coordination atoms. The concentrations of characteristic atoms in B2-NbMo type ordered alloys were calculated as functions of ordering degree（s） and composition Xuo. When S=Smax, the concentrations of characteristic atoms of stoichiometric B2-NbMo intermetallic compound are equal to that of alloys, that is, X8^Nb = 0.5 at, X0^Mo= 0.5 at. As ordering degree decreases, characteristic atoms A8^Nb and A0^Mo of B2-NbMo type ordered alloy split. And the degree of splitting of characteristic atoms increases with the ordering degree decreasing. Therefore, disordered alloys and various types of ordered alloys can be designed.
基金the financial support of the National Natural Science Foundation of China (21875206 and 21403187)China Postdoctoral Science Foundation (2015T80229)the Natural Science Foundation of Hebei Province (B2019203487)
文摘Organic quinone compounds have attracted wide attention due to their high theoretical capacities.Here,a novel cyclic macromolecular calix[6]quinone(C6Q),which possesses 6 p-quinone units and can provide 12 electrochemical active sites,has been applied as a promising cathode material in lithium ion batteries(LIBs).The as-fabricated LIBs exhibited an initial specific capacity as high as 423 mA h g^-1(Ctheo=447 mA h g^-1)at 0.1 C.After 100 cycles,the capacity of C6Q maintained at 216 mA h g^-1,and even after 300 cycles,C6Q still achieved a high specific capacity of 195 mA h g^-1 with negligible capacity fading(as compared with the 100th cycle).Due to the large capacity and wide electrochemical window,C6Q can deliver a specific energy up to 1201 W h kg^-1.In addition,the method of immobilizing C6Q with ordered mesoporous carbon(OMC)CMK-3 could further enhance the electrochemical performance of C6Q.
基金This work was supported by the Recruitment Program of Global Youth Experts of China, the National Natural Science Foundation of China （21403267, 21450110410）, and Shandong Postdoctoral Innovation Program （201303065）.
文摘Ordered mesoporous Cu-Mg-A1 composite oxides were synthesized via the one-pot evaporation-in- duced self-assembly strategy. Using this method, copper was first homogeneously incorporated into the ordered mesoporous spinel matrix. After H2 reduction treatment, according to X-ray diffraction （XRD） and transmission electron microscopy （TEM） results, copper existed as metallic nanoparticles with the size of 6-10 nm that well decorated the parent mesoporous skeleton. The metallic nanoparticles were then re-oxidized to copper oxide when exposed to air or during CO oxidation reaction at low temperatures. Thus, copper migrated from bulk spinel phase to the surface after the reduction-oxidation treat- ment. Moreover, the copper on the surface was re-incor- porated into the bulk spinel phase by further thermal treatment at much higher temperature in the presence of air. The correlation between the state of copper in the mesoporous composite oxides and the catalytic perfor- mance toward CO oxidation was studied. It was found that copper existed as oxide nanoparticles on the surface of mesoporous Mg-Al skeleton is much more active than that existed as lattice Cu ions in spinel phase.
