The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicompone...The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.展开更多
Recently,metal–organic frameworks are one of the potential catalytic materials for electrocatalytic applications.The oxygen reduction reaction and oxygen evolution reaction catalytic activities of heterometallic clus...Recently,metal–organic frameworks are one of the potential catalytic materials for electrocatalytic applications.The oxygen reduction reaction and oxygen evolution reaction catalytic activities of heterometallic cluster-based organic frameworks are investigated using density functional theory.Firstly,the catalytic activities of heterometallic clusters are investigated.Among all heterometallic clusters,Fe_(2)Mn–Mn has a minimum overpotential of 0.35 V for oxygen reduction reaction,and Fe_(2)Co–Co possesses the smallest overpotential of 0.32 V for oxygen evolution reaction,respectively 100 and 50 mV lower than those of Pt(111)and RuO_(2)(110)catalysts.The analysis of the potential gap of Fe_(2)M clusters indicates that Fe_(2)Mn,Fe_(2)Co,and Fe_(2)Ni clusters possess good bifunctional catalytic activity.Additionally,the catalytic activity of Fe_(2)Mn and Fe_(2)Co connected through 3,3′,5,5′-azobenzenetetracarboxylate linker to form Fe_(2)M–PCN–Fe_(2)M is explored.Compared with Fe_(2)Mn–PCN–Fe_(2)Mn,Fe_(2)Co–PCN–Fe_(2)Co,and isolated Fe_(2)M clusters,the mixed-metal Fe_(2)Co–PCN–Fe_(2)Mn possesses excellent bifunctional catalytic activity,and the values of potential gap on the Mn and Co sites of Fe_(2)Co–PCN–Fe_(2)Mn are 0.69 and 0.70 V,respectively.Furthermore,the analysis of the electron structure indicates that constructing a mixed-metal cluster can efficiently enhance the electronic properties of the catalyst.In conclusion,the mixed-metal cluster strategy provides a new approach to further design and synthesize high-efficiency bifunctional electrocatalysts.展开更多
Ultra-narrow linewidth laser with several hundred hertz at room temperature has attracted a great deal of attention in recent years and played a critical role in both optical sensing and communication fields. In this ...Ultra-narrow linewidth laser with several hundred hertz at room temperature has attracted a great deal of attention in recent years and played a critical role in both optical sensing and communication fields. In this paper, a new method based on Rayleigh backscattering to highly compress the laser linewidth was proposed and demonstrated theoretically and experimentally. By theoretical analysis and simulation, Rayleigh backscattering can be collected in any waveguide structure and all wave bands,which could have a revolutionary impact on the field of laser. A single-longitudinal mode fiber ring laser with130-Hz linewidth was achieved with self-injection feedback structure at normal atmospheric temperature. The linewidth compression based on Rayleigh backscattering lies in the fact that laser linewidth after scattering is narrower than that of incident light in high Rayleigh scattering structure. The self-rejection feedback method expanding free spectra range of laser cavity simultaneously was used to further suppress the mode-hopping and stabilizing output. Experimental results showed that the laser linewidth can be easily narrowed to hundreds of hertz with side-mode suppression up to 75 dB. This agrees with the theoretical analysis and simulation results qualitatively.展开更多
An experimental analysis on the subsequent yield-surfaces evolution using multiple specimens is presented for a 45 steel after a prescribed pre-strain loading in three different directions respectively, and the yieldi...An experimental analysis on the subsequent yield-surfaces evolution using multiple specimens is presented for a 45 steel after a prescribed pre-strain loading in three different directions respectively, and the yielding is defined by a designated offsetting strain. The size of the subsequent yield surface is found smaller than the initial yield surface; the negative cross effects are observed in the normal loading direction, its shape is not a Mises circle but has a rather blunt nose in loading direction and flat in the opposite. These results strongly depend on the loading path and the prescribed offset plastic strain. The plastic flow direction to the subsequent yield surface is investigated, and it is found that the plastic flow direction deviates from the normal flow rule. The deviation differs from preloading case to preloading case. And the plastic flow direction would have a larger deviation from the normal of the yield surface, if the subsequent yield was defined by a smaller offset strain. Furthermore, the experiments are simulated using the Chaboche model, and the results show that it can rationally predict yield-surface only when yield is defined by a fairly large offset strain.展开更多
基金This work was financially supported by“High-Level Youth Talent Special Support Plan”of Kunming City(C202014002)the National Natural Science Foundation of China(51904137)+3 种基金the Applied Basic Research Projects of Yunnan Province(2019FD044)the Open Projects of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(CNMRCUKF1905)the Talent Training Project of Kunming University(YJL2102)The authors are grateful to NSFC and“High-Level Talent Special Support Plan”of Kunming City(C201905002).
文摘The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.
基金supported by the Science and Technology Project of Sichuan Province(Grant No.2022YFS0447)the Local Science and Technology Development Fund Projects Guided by the Central Government of China(Grant No.2021ZYD0060)+2 种基金the Science and Technology Project of Southwest Petroleum University(Grant No.2021JBGS03)the Special Project of Science and Technology Strategic Cooperation between Nanchong City and Southwest Petroleum University(Grant No.SXQHJH064)the Postgraduate Research and Innovation Fund of Southwest Petroleum University(Grant No.2021CXYB14).
文摘Recently,metal–organic frameworks are one of the potential catalytic materials for electrocatalytic applications.The oxygen reduction reaction and oxygen evolution reaction catalytic activities of heterometallic cluster-based organic frameworks are investigated using density functional theory.Firstly,the catalytic activities of heterometallic clusters are investigated.Among all heterometallic clusters,Fe_(2)Mn–Mn has a minimum overpotential of 0.35 V for oxygen reduction reaction,and Fe_(2)Co–Co possesses the smallest overpotential of 0.32 V for oxygen evolution reaction,respectively 100 and 50 mV lower than those of Pt(111)and RuO_(2)(110)catalysts.The analysis of the potential gap of Fe_(2)M clusters indicates that Fe_(2)Mn,Fe_(2)Co,and Fe_(2)Ni clusters possess good bifunctional catalytic activity.Additionally,the catalytic activity of Fe_(2)Mn and Fe_(2)Co connected through 3,3′,5,5′-azobenzenetetracarboxylate linker to form Fe_(2)M–PCN–Fe_(2)M is explored.Compared with Fe_(2)Mn–PCN–Fe_(2)Mn,Fe_(2)Co–PCN–Fe_(2)Co,and isolated Fe_(2)M clusters,the mixed-metal Fe_(2)Co–PCN–Fe_(2)Mn possesses excellent bifunctional catalytic activity,and the values of potential gap on the Mn and Co sites of Fe_(2)Co–PCN–Fe_(2)Mn are 0.69 and 0.70 V,respectively.Furthermore,the analysis of the electron structure indicates that constructing a mixed-metal cluster can efficiently enhance the electronic properties of the catalyst.In conclusion,the mixed-metal cluster strategy provides a new approach to further design and synthesize high-efficiency bifunctional electrocatalysts.
基金supported by the National Natural Science Foundation of China(61377066)the Fundamental Research Funds for the Central Universities(CDJZR12125502,106112013CDJZR120002,and 106112013CDJZR160006)
文摘Ultra-narrow linewidth laser with several hundred hertz at room temperature has attracted a great deal of attention in recent years and played a critical role in both optical sensing and communication fields. In this paper, a new method based on Rayleigh backscattering to highly compress the laser linewidth was proposed and demonstrated theoretically and experimentally. By theoretical analysis and simulation, Rayleigh backscattering can be collected in any waveguide structure and all wave bands,which could have a revolutionary impact on the field of laser. A single-longitudinal mode fiber ring laser with130-Hz linewidth was achieved with self-injection feedback structure at normal atmospheric temperature. The linewidth compression based on Rayleigh backscattering lies in the fact that laser linewidth after scattering is narrower than that of incident light in high Rayleigh scattering structure. The self-rejection feedback method expanding free spectra range of laser cavity simultaneously was used to further suppress the mode-hopping and stabilizing output. Experimental results showed that the laser linewidth can be easily narrowed to hundreds of hertz with side-mode suppression up to 75 dB. This agrees with the theoretical analysis and simulation results qualitatively.
基金Project supported by the National Natural Science Foundation of China(Nos.90815001and11072064)Key Project of Guangxi Science and Technology Lab Center(No.LGZX201101)
文摘An experimental analysis on the subsequent yield-surfaces evolution using multiple specimens is presented for a 45 steel after a prescribed pre-strain loading in three different directions respectively, and the yielding is defined by a designated offsetting strain. The size of the subsequent yield surface is found smaller than the initial yield surface; the negative cross effects are observed in the normal loading direction, its shape is not a Mises circle but has a rather blunt nose in loading direction and flat in the opposite. These results strongly depend on the loading path and the prescribed offset plastic strain. The plastic flow direction to the subsequent yield surface is investigated, and it is found that the plastic flow direction deviates from the normal flow rule. The deviation differs from preloading case to preloading case. And the plastic flow direction would have a larger deviation from the normal of the yield surface, if the subsequent yield was defined by a smaller offset strain. Furthermore, the experiments are simulated using the Chaboche model, and the results show that it can rationally predict yield-surface only when yield is defined by a fairly large offset strain.
