The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of ar...The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of artificial intelligence.Based on the analysis of the major factors affecting the scale of enlarged production,we first interpreted in detail the design principles and structure of the intelligent system.Secondly,we introduced an ANN subsystem.In order to ensure technological and scale efficien- cies of the training samples for ANN,we filtrated the samples with a DEA method.Finally,we trained the intelligent system,which was proved to be very efficient.展开更多
A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for...A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.展开更多
Forced convective experiment of supercritical water was performed in Inconel-625 tubes of 4.62 mm, 7.98 mm and 10.89 mm in diameter. The water flowed upward, covering the ranges of pressure of 23.4 MPa to 25.8 MPa, ma...Forced convective experiment of supercritical water was performed in Inconel-625 tubes of 4.62 mm, 7.98 mm and 10.89 mm in diameter. The water flowed upward, covering the ranges of pressure of 23.4 MPa to 25.8 MPa, mass flux of 90 kg/m^2s to 3,281 kg/m^2s, local bulk temperature of 102-384 ℃, inner wall temperature of 167-669℃ and heat flux of up to 2.41 MW/m^2. The results exhibited severe deteriorated and enhancement heat transfer. The experimental results can be calculated by the Jackson＇s correlation and the Bishop＇s correlation mostly. But some data with strong effects of the buoyancy force and the variations of flow regimes can not be predicted properly.展开更多
Transport properties of LaFeO3 in the temperature range of 2 K 〈 T 〈 300 K have been explored for the first time using interaction potential developed by the author and found that our computed results on transport p...Transport properties of LaFeO3 in the temperature range of 2 K 〈 T 〈 300 K have been explored for the first time using interaction potential developed by the author and found that our computed results on transport properties follow the same trend as that of available experimental values. These are scientifically and technologically important materials with orthorhombic perovskite-like structure and space group Pbnm. Lanthanum ferrite, LaFeO3 is semiconducting and antiferrom agnetically ordered at zero. The thermodynamics of perovskite-type or related materials of potential use in, e.g., solid oxide fuel cells have been studied to a rather limited extent only.展开更多
A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures （FTHs） by combining the versatility of the electrospinning technique and the hydrother...A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures （FTHs） by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe304 and the unique features of the hierarchical nanofibers.展开更多
Electrocaloric effect （ECE） is much promising to realize high efficiency and environment friendly solution in solid cooling devices. Relaxor ferroelectrics are good candidates for the materials with high elec-trocal...Electrocaloric effect （ECE） is much promising to realize high efficiency and environment friendly solution in solid cooling devices. Relaxor ferroelectrics are good candidates for the materials with high elec-trocaloric cooling power. In this paper, relaxor ferroelectric Ba（ZrxTil_x）O3 （BZT, x = 0.2, 0.21, 0.22, 0.23） ceramics were prepared with their temperature change （AT） induced by the ECE and electrocaloric strength （AT/E） measured within broad temperature range. It is found that the BZT21 （x = 0.21) exhibits the largest ATof-4.67 K and a high AT/E value of-0.46 km/MV at 9.9 MV/m and 25℃. BZT21 also exhi-bits apparent relaxor ferroelectric response, showing a very broad EC peak in the temperature interval between 15℃ and 50℃. Moreover, the relationship between EC properties and relaxor features was analyzed by piezoresponse force microscopy test. The results reveal that more dispersed phase structures induce additional configurational entropy, which is in favor for the enhanced EC performance. The inter-play and compromise between the kinetic and thermodynamic mechanisms of domain switching deter-mines the optimal composition for the EC performances of the BZT ceramics.展开更多
基金Project 50374005 supported by the National Natural Science Foundation of China
文摘The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of artificial intelligence.Based on the analysis of the major factors affecting the scale of enlarged production,we first interpreted in detail the design principles and structure of the intelligent system.Secondly,we introduced an ANN subsystem.In order to ensure technological and scale efficien- cies of the training samples for ANN,we filtrated the samples with a DEA method.Finally,we trained the intelligent system,which was proved to be very efficient.
基金sponsored by projects (Grant Nos. 50978172, 51078318) of the National Natural Science Foundation of ChinaProject (Grant No. 10-0667) supposed by the New Century Excellent Talents in University
文摘A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.
文摘Forced convective experiment of supercritical water was performed in Inconel-625 tubes of 4.62 mm, 7.98 mm and 10.89 mm in diameter. The water flowed upward, covering the ranges of pressure of 23.4 MPa to 25.8 MPa, mass flux of 90 kg/m^2s to 3,281 kg/m^2s, local bulk temperature of 102-384 ℃, inner wall temperature of 167-669℃ and heat flux of up to 2.41 MW/m^2. The results exhibited severe deteriorated and enhancement heat transfer. The experimental results can be calculated by the Jackson＇s correlation and the Bishop＇s correlation mostly. But some data with strong effects of the buoyancy force and the variations of flow regimes can not be predicted properly.
文摘Transport properties of LaFeO3 in the temperature range of 2 K 〈 T 〈 300 K have been explored for the first time using interaction potential developed by the author and found that our computed results on transport properties follow the same trend as that of available experimental values. These are scientifically and technologically important materials with orthorhombic perovskite-like structure and space group Pbnm. Lanthanum ferrite, LaFeO3 is semiconducting and antiferrom agnetically ordered at zero. The thermodynamics of perovskite-type or related materials of potential use in, e.g., solid oxide fuel cells have been studied to a rather limited extent only.
基金This work is financially supported by the fundamental research funds for the central universities, the National Natural Science Foundation of China （Grant Nos. 51372007 and 21301014）.
文摘A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures （FTHs） by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe304 and the unique features of the hierarchical nanofibers.
基金supported by the National Natural Science Foundation of China (51625202,51532003,and 51572141)the National Basic Research Program of China (2015CB654603)National Key Research & Development Program of China (2017YFB0701603)
文摘Electrocaloric effect （ECE） is much promising to realize high efficiency and environment friendly solution in solid cooling devices. Relaxor ferroelectrics are good candidates for the materials with high elec-trocaloric cooling power. In this paper, relaxor ferroelectric Ba（ZrxTil_x）O3 （BZT, x = 0.2, 0.21, 0.22, 0.23） ceramics were prepared with their temperature change （AT） induced by the ECE and electrocaloric strength （AT/E） measured within broad temperature range. It is found that the BZT21 （x = 0.21) exhibits the largest ATof-4.67 K and a high AT/E value of-0.46 km/MV at 9.9 MV/m and 25℃. BZT21 also exhi-bits apparent relaxor ferroelectric response, showing a very broad EC peak in the temperature interval between 15℃ and 50℃. Moreover, the relationship between EC properties and relaxor features was analyzed by piezoresponse force microscopy test. The results reveal that more dispersed phase structures induce additional configurational entropy, which is in favor for the enhanced EC performance. The inter-play and compromise between the kinetic and thermodynamic mechanisms of domain switching deter-mines the optimal composition for the EC performances of the BZT ceramics.
