To improve the charging of high-temperature billets, it is crucial to produce them with zero defects and achieve effective insulation during their hot delivery. A mathematical model was developed based on the heat tra...To improve the charging of high-temperature billets, it is crucial to produce them with zero defects and achieve effective insulation during their hot delivery. A mathematical model was developed based on the heat transfer characteristics of the billet during its hot delivery. The accuracy of the model was established by studying the thermal performance of the cover of the roller conveyer for small billets in Tangshan Iron and Steel Company. The results show that the cover of the roller conveyer of the continuous casting billet can effectively reduce the heat loss during the hot delivery of the billets, and the hot loading temperature was increased by 51.6 °C. The uniformity of the temperature of the casting billet section increased substantially. The temperature difference in the casting billet section was reduced by 120 °C. The heat preservation effects of temperature holding hoods of different materials were compared. It was found that the material of the temperature holding hood has slight effect on the heat preservation.展开更多
According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill t...According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.展开更多
Blast furnace operation with hot burden charging was numerically simulated to preliminarily analyze its advantages and disadvantages. Multi-fluid blast furnace model was utilized to simulate hot burden charging operat...Blast furnace operation with hot burden charging was numerically simulated to preliminarily analyze its advantages and disadvantages. Multi-fluid blast furnace model was utilized to simulate hot burden charging operations under the conditions that the charging temperatures of pellet and coke were supposed separately or simultaneously as 800℃. The results showed that, with hot burden charging, the furnace top temperature significantly increased in comparison to the conventional operation with cold hurden charging. However, in-furnace temperature decreased, which decelerated the reduction rate of ferrous burdens. The concentrations of reducing gases were decreased in the furnace. The height of cohesive zone shifted downwards. When the charging temperatures of pellet and coke were simultaneously 800 ~C （PC800）, coke rate, fuel rate and carbon emission rate were decreased by 13.4, 22.1 and 19.25 kg ~ t-1 , respectively. The ratio of ore to coke, solid burden charging rate and hot metal productivity were increased by 4. 790%, 7.55 kg · s^- 1 and 6.38%, respectively. Heat taken away by top gas and energy consumption per ton hot metal were increased by 68.97% and 6.40%, respectively. Generally speaking, hot burden charging was ad verse to energy utilization of blast furnace.展开更多
This paper presented the application of the direct hot charge rolling （DHCR） technology in Ningbo Steel. Five aspects have been systematically addressed and analyzed, which include sales order, production schedule p...This paper presented the application of the direct hot charge rolling （DHCR） technology in Ningbo Steel. Five aspects have been systematically addressed and analyzed, which include sales order, production schedule programming, steelmaking,continuous casting and hot-rolling. The average DHCR product rate has reached 55% and the average slab charging temperature 699℃. As a result, the production cost, the energy consumption and the CO2emission have been significantly reduced. It is concluded that a breakthrough in application of the DHCR technology has been achieved at Ningbo Steel.展开更多
Effect of hot and cold dust charge on the propagation of dust-acoustic waves （DAWs） in unmagnetized plasma having electrons, singly charged ions, hot and cold dust grains has been investigated. The reductive perturb...Effect of hot and cold dust charge on the propagation of dust-acoustic waves （DAWs） in unmagnetized plasma having electrons, singly charged ions, hot and cold dust grains has been investigated. The reductive perturbation method is employed to reduce the basic set of fluid equations to the Kortewege-de Vries （KdV） equation. At the critical hot dusty plasma density Nho, the KdV equation is not appropriate for describing the system. Hence, a set of stretched coordinates is considered to derive the modified KdV equation. It is found that the presence of hot and cold dust charge grains not only significantly modifies the basic properties of solitary structure, but also changes the polarity of the solitary profiles. In the vicinity of the critical hot dusty plasma density Nho, neither KdV nor mKdV equation is appropriate for describing the DAWs. Therefore, a further modified KdV （fmKdV） equation is derived, which admits both soliton and double layer solutions.展开更多
This paper summarizes our recent works on theoretical modelling of molecular packing and electronic processes in small-molecule organic solar cells.Firstly,we used quantum-chemical calculations to illustrate exciton-d...This paper summarizes our recent works on theoretical modelling of molecular packing and electronic processes in small-molecule organic solar cells.Firstly,we used quantum-chemical calculations to illustrate exciton-dissociation and charge-recombination processes at the DTDCTB/C_（60） interface and particularly emphasized the major role of hot charge-transfer states in the exciton-dissociation processes.Then,we systematically analyzed the influence of DTDCTB surfaces with different features on the vacuum vapor deposition growth and packing morphologies of C_（60） via atomistic molecular dynamics simulations,and found that the formation of crystalline fullerene is the result of an integrated impact of stability,landscape,and molecular orientation of the substrate surfaces.Also,we investigated the impact of different film-processing conditions,such as solvent evaporation rates and thermal annealing,on molecular packing configurations in a neat small-molecule donor material,DPP（TBFu）_2,and discussed the correlation between charge mobility and molecular packing via atomistic simulations in combination with electronic-structure calculations and kinetic Monte Carlo simulations.展开更多
文摘To improve the charging of high-temperature billets, it is crucial to produce them with zero defects and achieve effective insulation during their hot delivery. A mathematical model was developed based on the heat transfer characteristics of the billet during its hot delivery. The accuracy of the model was established by studying the thermal performance of the cover of the roller conveyer for small billets in Tangshan Iron and Steel Company. The results show that the cover of the roller conveyer of the continuous casting billet can effectively reduce the heat loss during the hot delivery of the billets, and the hot loading temperature was increased by 51.6 °C. The uniformity of the temperature of the casting billet section increased substantially. The temperature difference in the casting billet section was reduced by 120 °C. The heat preservation effects of temperature holding hoods of different materials were compared. It was found that the material of the temperature holding hood has slight effect on the heat preservation.
文摘According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.
基金Item Sponsored by National Natural Science Foundation of China(50804008)Program for New Century Excellent Talents in University of China(NCET-08-0099)
文摘Blast furnace operation with hot burden charging was numerically simulated to preliminarily analyze its advantages and disadvantages. Multi-fluid blast furnace model was utilized to simulate hot burden charging operations under the conditions that the charging temperatures of pellet and coke were supposed separately or simultaneously as 800℃. The results showed that, with hot burden charging, the furnace top temperature significantly increased in comparison to the conventional operation with cold hurden charging. However, in-furnace temperature decreased, which decelerated the reduction rate of ferrous burdens. The concentrations of reducing gases were decreased in the furnace. The height of cohesive zone shifted downwards. When the charging temperatures of pellet and coke were simultaneously 800 ~C （PC800）, coke rate, fuel rate and carbon emission rate were decreased by 13.4, 22.1 and 19.25 kg ~ t-1 , respectively. The ratio of ore to coke, solid burden charging rate and hot metal productivity were increased by 4. 790%, 7.55 kg · s^- 1 and 6.38%, respectively. Heat taken away by top gas and energy consumption per ton hot metal were increased by 68.97% and 6.40%, respectively. Generally speaking, hot burden charging was ad verse to energy utilization of blast furnace.
文摘This paper presented the application of the direct hot charge rolling （DHCR） technology in Ningbo Steel. Five aspects have been systematically addressed and analyzed, which include sales order, production schedule programming, steelmaking,continuous casting and hot-rolling. The average DHCR product rate has reached 55% and the average slab charging temperature 699℃. As a result, the production cost, the energy consumption and the CO2emission have been significantly reduced. It is concluded that a breakthrough in application of the DHCR technology has been achieved at Ningbo Steel.
文摘Effect of hot and cold dust charge on the propagation of dust-acoustic waves （DAWs） in unmagnetized plasma having electrons, singly charged ions, hot and cold dust grains has been investigated. The reductive perturbation method is employed to reduce the basic set of fluid equations to the Kortewege-de Vries （KdV） equation. At the critical hot dusty plasma density Nho, the KdV equation is not appropriate for describing the system. Hence, a set of stretched coordinates is considered to derive the modified KdV equation. It is found that the presence of hot and cold dust charge grains not only significantly modifies the basic properties of solitary structure, but also changes the polarity of the solitary profiles. In the vicinity of the critical hot dusty plasma density Nho, neither KdV nor mKdV equation is appropriate for describing the DAWs. Therefore, a further modified KdV （fmKdV） equation is derived, which admits both soliton and double layer solutions.
基金the financial support from the National Natural Science Foundation of China(No.91333117)the National Basic Research (973) Program of the Ministry of Science and Technology of China(No.2014CB643506)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB12020200)
文摘This paper summarizes our recent works on theoretical modelling of molecular packing and electronic processes in small-molecule organic solar cells.Firstly,we used quantum-chemical calculations to illustrate exciton-dissociation and charge-recombination processes at the DTDCTB/C_（60） interface and particularly emphasized the major role of hot charge-transfer states in the exciton-dissociation processes.Then,we systematically analyzed the influence of DTDCTB surfaces with different features on the vacuum vapor deposition growth and packing morphologies of C_（60） via atomistic molecular dynamics simulations,and found that the formation of crystalline fullerene is the result of an integrated impact of stability,landscape,and molecular orientation of the substrate surfaces.Also,we investigated the impact of different film-processing conditions,such as solvent evaporation rates and thermal annealing,on molecular packing configurations in a neat small-molecule donor material,DPP（TBFu）_2,and discussed the correlation between charge mobility and molecular packing via atomistic simulations in combination with electronic-structure calculations and kinetic Monte Carlo simulations.
