Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the co...Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.展开更多
To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted ...To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame(CSF) distributes uniformly; and each high-strength bolt(HSB)primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly; and the HSBs at both ends of the CSF transfer the maximum shear forces.展开更多
Serious accidents of mine hoists caused by high-speed sliding between friction lining and wire rope are often seen in coal mines.In order to solve this problem,we analyzed the contact characteristics between friction ...Serious accidents of mine hoists caused by high-speed sliding between friction lining and wire rope are often seen in coal mines.In order to solve this problem,we analyzed the contact characteristics between friction lining and wire rope.Then we carried out a dynamic mechanical analysis(DMA) to explain the change in mechanical properties of the friction lining as function of temperature and load frequency and found that temperature has a stronger effect on the mechanical properties than the frequency.We used multiple regression analysis to obtain the thermoviscoelastic constitutive relations of the friction lining.As well we derived the analytic solution for the thermoviscoelastic contact radius and pressure by combining the theory of viscoelastic contact mechanics with thermoviscoelastic constitutive relations.展开更多
The Ga-Hg binary system was thermodynamically assessed by the CALPHAD method, but only configuration contributions were considered to the entropy of the liquid. The Mg-Hg binary system has not been assessed yet. In th...The Ga-Hg binary system was thermodynamically assessed by the CALPHAD method, but only configuration contributions were considered to the entropy of the liquid. The Mg-Hg binary system has not been assessed yet. In the assessments of the Ga-Hg and Mg-Hg binary systems, solutions including liquid and hcp (Mg) were treated as substitution solutions, of which the excess Gibbs energies were formulated with the Relich-Kister polynomial. The intermetallic phases in the Mg-Hg binary system, Mg3Hg, Mg5Hg2, Mg2Hg, Mg5Hg3, MgHg, and MgHg2, were described as stoichiometric compounds. Based on the reported experimental data and thermodynamic properties of the phase diagram, sets of self-consistent parameters describing all phases in the Ga-Hg and the Mg-Hg binary systems were obtained.展开更多
This case concerns the evaluation of a capital investment and provides an opportunity to conduct a sensitivity analysis of outcomes based on alternative project assumptions. Optimum production outputs depend on a reli...This case concerns the evaluation of a capital investment and provides an opportunity to conduct a sensitivity analysis of outcomes based on alternative project assumptions. Optimum production outputs depend on a reliable fleet of minesite vehicles. Replacement and maintenance alternatives need to be assessed and managed to ensure effective outcomes.展开更多
基金Project(50474083) supported by the National Natural Science Foundation of ChinaProject supported by the Baoshan Iron & Steel Co. Ltd. of China
文摘Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.
基金Project(51078077)supported by the National Natural Science Foundation of China
文摘To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame(CSF) distributes uniformly; and each high-strength bolt(HSB)primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly; and the HSBs at both ends of the CSF transfer the maximum shear forces.
基金Projects 50875253 supported by the National Natural Science Foundation of China20060290505 by the Research Fund for the Doctoral Program of Higher Education of China+2 种基金107054 by the Key Project of Ministry of Education of ChinaBK2008127 by the Natural Science Foundation of Jiangsu ProvinceCX08B_042Z by the Scientific Innovation Program for Postgraduates in Colleges and Universities of Jiangsu Province
文摘Serious accidents of mine hoists caused by high-speed sliding between friction lining and wire rope are often seen in coal mines.In order to solve this problem,we analyzed the contact characteristics between friction lining and wire rope.Then we carried out a dynamic mechanical analysis(DMA) to explain the change in mechanical properties of the friction lining as function of temperature and load frequency and found that temperature has a stronger effect on the mechanical properties than the frequency.We used multiple regression analysis to obtain the thermoviscoelastic constitutive relations of the friction lining.As well we derived the analytic solution for the thermoviscoelastic contact radius and pressure by combining the theory of viscoelastic contact mechanics with thermoviscoelastic constitutive relations.
文摘The Ga-Hg binary system was thermodynamically assessed by the CALPHAD method, but only configuration contributions were considered to the entropy of the liquid. The Mg-Hg binary system has not been assessed yet. In the assessments of the Ga-Hg and Mg-Hg binary systems, solutions including liquid and hcp (Mg) were treated as substitution solutions, of which the excess Gibbs energies were formulated with the Relich-Kister polynomial. The intermetallic phases in the Mg-Hg binary system, Mg3Hg, Mg5Hg2, Mg2Hg, Mg5Hg3, MgHg, and MgHg2, were described as stoichiometric compounds. Based on the reported experimental data and thermodynamic properties of the phase diagram, sets of self-consistent parameters describing all phases in the Ga-Hg and the Mg-Hg binary systems were obtained.
文摘This case concerns the evaluation of a capital investment and provides an opportunity to conduct a sensitivity analysis of outcomes based on alternative project assumptions. Optimum production outputs depend on a reliable fleet of minesite vehicles. Replacement and maintenance alternatives need to be assessed and managed to ensure effective outcomes.