The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial directi...The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial direction,and the compensation model.Based on the rule of volume flow rate,the dynamic rolling process model was built.The work roll and backup roll were taken as elastic continuous bodies,the effect of shear and moment of inertia were taken into consideration,and then the dynamic model of rolls was built.The two models were coupled together,and the dynamic model of rolling mill was built.In the dynamic model,the thermal expansion of the rolls,the wear of the rolls and other related parameters can not be considered.In order to compensate the dynamic model,the coupled static model of rolls and strip was applied.Then,according to the inner relationship of these models,the dynamic model and the compensation model were coupled,and the dynamic model of rolling mill based on the strip flatness and thickness integrated control was built.The dynamic simulation of the rolling process was made,and the dynamic thickness and the dynamic flatness information were obtained.This model not only provides a theory basis for the virtual rolling,but also provides a platform for the application of advanced control theory.展开更多
The accuracy of present flatness predictive method is limited and it just belongs to software simulation. In order to improve it, a novel flatness predictive model via T-S cloud reasoning network implemented by digita...The accuracy of present flatness predictive method is limited and it just belongs to software simulation. In order to improve it, a novel flatness predictive model via T-S cloud reasoning network implemented by digital signal processor(DSP) is proposed. First, the combination of genetic algorithm(GA) and simulated annealing algorithm(SAA) is put forward, called GA-SA algorithm, which can make full use of the global search ability of GA and local search ability of SA. Later, based on T-S cloud reasoning neural network, flatness predictive model is designed in DSP. And it is applied to 900 HC reversible cold rolling mill. Experimental results demonstrate that the flatness predictive model via T-S cloud reasoning network can run on the hardware DSP TMS320 F2812 with high accuracy and robustness by using GA-SA algorithm to optimize the model parameter.展开更多
The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and...The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations.A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control.In comparison with the conventional backup and work roll contours configuration,the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls(ASR) and varying contact backup rolls(VCR).A better strip profile and flatness quality,an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.展开更多
To overcome the disadvantage that the standard least squares support vector regression(LS-SVR) algorithm is not suitable to multiple-input multiple-output(MIMO) system modelling directly,an improved LS-SVR algorithm w...To overcome the disadvantage that the standard least squares support vector regression(LS-SVR) algorithm is not suitable to multiple-input multiple-output(MIMO) system modelling directly,an improved LS-SVR algorithm which was defined as multi-output least squares support vector regression(MLSSVR) was put forward by adding samples' absolute errors in objective function and applied to flatness intelligent control.To solve the poor-precision problem of the control scheme based on effective matrix in flatness control,the predictive control was introduced into the control system and the effective matrix-predictive flatness control method was proposed by combining the merits of the two methods.Simulation experiment was conducted on 900HC reversible cold roll.The performance of effective matrix method and the effective matrix-predictive control method were compared,and the results demonstrate the validity of the effective matrix-predictive control method.展开更多
An innovative flat heat pipe radiator was put forward, and it has the features of high efficiency of heat dissipation, compact construction, low thermal resistance, light weight, low cost, and anti-dust-deposition. Th...An innovative flat heat pipe radiator was put forward, and it has the features of high efficiency of heat dissipation, compact construction, low thermal resistance, light weight, low cost, and anti-dust-deposition. The thermal analysis of the flat heat pipe radiator for cooling high-power light emitting diode （LED） array was conducted. The thermal characteristics of the flat heat pipe radiator under the different heat loads and incline angles were investigated experimentally in natural convection. An electro-thermal conversion method was used to measure the junction temperature of the LED chips. It is found that the integral temperature distribution of the flat heat pipe radiator is reasonable and uniform. The total thermal resistance of the flat heat pipe radiator varies in the range of 0.38-0.45 K/W. The junction temperatures of LED chips with the flat heat pipe radiator and with the aluminum board at the same forward current of 0.35 A are 52.5 and 75.2 ℃, respectively.展开更多
Based on the study on cultivation models of soybean narrow-row-flat-dense planting under the conditions of different between-row spacing and inter-plant spacing by using the comparison field experiment, and technical ...Based on the study on cultivation models of soybean narrow-row-flat-dense planting under the conditions of different between-row spacing and inter-plant spacing by using the comparison field experiment, and technical studies of the contour following the seeder unit, the anti-block, the lateral and stratified the deep fertilizing, according to the design ideas of planting units integration and variable between-row spacing from 30 to 45 cm, the 2BZJ-3/4 precision planter matched with 18-32 hp tractors has been developed for the popularization of the narrow-row-flat-dense planting soybean technique by means of Virtual Prototyping （VP） technology.展开更多
Two fundamental hypotheses of special relativistic gravitational theory are: (1) the equivalence of gravitational mass and inertial mass, (2) the equation of the gravitational tensor potential in linear approximat...Two fundamental hypotheses of special relativistic gravitational theory are: (1) the equivalence of gravitational mass and inertial mass, (2) the equation of the gravitational tensor potential in linear approximation. Main results: (1) the values of the planetary perihelion shill, and the angle of deflection of light are the same as those of general relativity. The value of the red shill is consistent with the experiment. One cannot use these experimental values to judge whether space-time is curved. (2) In GP-B experiment, the gyroscope will be acted on by the additional gravitational fields due to the Earth's spin (S) and the orbital motion of satellite (L). The average precession rates are , where β and δ are the gyroscope's polar angles, (S) and (G) designate values deduced from special and general relativity, respectively. The GP-B experiment is the first one to judge whether space-time is flat.展开更多
As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous f...As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern adaptability.Through experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow curve.The results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well pattern.With the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational increase.Under the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.展开更多
An investigation has been carried out to compare th e cutting performance and tool life evaluation of high speed steel broach samp les. The comparison has been done between conventional M2 and Anti-Segregation Process...An investigation has been carried out to compare th e cutting performance and tool life evaluation of high speed steel broach samp les. The comparison has been done between conventional M2 and Anti-Segregation Process (ASP) ASP53 and ASP30 high speed steel broach samples. The ASP53 was a development material. The cutting performance was evaluated by measuring the c utting forces and calculating the specific cutting energy, an indicator of cutti ng performance. As the roughness of the machined surface is an important criter ion in the evaluation of performance of a tool, the surface roughness of the workpiece was studied as a function of undeformed chip thickness. The workpiec e material was 150M36 alloy steel used in manufacture of automobile engines. Th e performance tests were conducted at two cutting speeds, which were 0 7 m/min and 10.5 m/min respectively. This allowed a better understanding of the effect of cutting speed on tool performance. The wear tests were performed at a cuttin g speed on 10.5 m/min. The cutting edges of ASP broach samples were finer compared to that of M2. Ther e was no practical difference in the cutting forces and the specific cutting ene rgy while cutting with MS, ASP30 and ASP53 broach samples. The ASP30 and ASP53 tools have a better surface roughness on the machined surface than that of M2 at both cutting speeds. The ASP30 gave 2.25 times the life and an improved surfac e finish compared to M2 steel. The ASP53 gave 1.3 times the life of M2 steel. These results should prove useful to the tool designer and manufacturing enginee r.展开更多
The influence of sand dust on discharge of external insulation has caused widespread concern.At present,the research results show wind-sand electricity has a remarkable effect on the discharge characteristics of insul...The influence of sand dust on discharge of external insulation has caused widespread concern.At present,the research results show wind-sand electricity has a remarkable effect on the discharge characteristics of insulator and has little influence on the discharge characteristics of air gap.The flashover of insulator strings occurs along the insulator surface and air gaps,and the sand dust deposited on the insulator surface may affect the flashover characteristics of insulator strings.This paper studies the flashover characteristics of flat plate model under DC voltage in wind-sand condition.The experimental results show that under positive polarity voltage,the flashover voltage of the flat plate model has a maximum value,while under negative polarity voltage,the flashover voltage of the flat plate model has a minimum value with a certain degree of sand dust deposition.The wind or sand in sand-dust weather has an important effect on the flashover characteristics of the flat plate model.In certain variation range of electric charge,electric charge of sand dust has little effect on the flashover voltage of flat plate model under DC voltage.The deposition of sand has significant influence on the flashover process of flat plate model,which is related to the deposition density and moisture content of sand particle.展开更多
A novel all-fibre flat-top comb filter based on a high birefringence photonic crystal fibre loop mirror is proposed and demonstrated. We simulate theoretically its output spectra and experimentally realize a flat-top ...A novel all-fibre flat-top comb filter based on a high birefringence photonic crystal fibre loop mirror is proposed and demonstrated. We simulate theoretically its output spectra and experimentally realize a flat-top output with a high extinction ratio. Compared to filters consisting of the conventional Panda polarization maintaining fibre, filters based on a high birefringence photonic crystal fibre loop mirror have better temperature stability. This kind of filter can be expected to be used widely in Wavelength-division-multiplexing(WDM) systems in the future.展开更多
基金Project(E2012203177)supported by the Natural Science Foundation of Hebei Province,ChinaProject(2011BAF15B01)supported by the National Science and Technology Support Plan of China+1 种基金Project(E2006001038)supported by Great Natural Science Foundation of Hebei Province,ChinaProject(NECSR-201202)supported by Open Project Program of National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,China
文摘The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial direction,and the compensation model.Based on the rule of volume flow rate,the dynamic rolling process model was built.The work roll and backup roll were taken as elastic continuous bodies,the effect of shear and moment of inertia were taken into consideration,and then the dynamic model of rolls was built.The two models were coupled together,and the dynamic model of rolling mill was built.In the dynamic model,the thermal expansion of the rolls,the wear of the rolls and other related parameters can not be considered.In order to compensate the dynamic model,the coupled static model of rolls and strip was applied.Then,according to the inner relationship of these models,the dynamic model and the compensation model were coupled,and the dynamic model of rolling mill based on the strip flatness and thickness integrated control was built.The dynamic simulation of the rolling process was made,and the dynamic thickness and the dynamic flatness information were obtained.This model not only provides a theory basis for the virtual rolling,but also provides a platform for the application of advanced control theory.
基金Project(E2015203354)supported by Natural Science Foundation of Steel United Research Fund of Hebei Province,ChinaProject(ZD2016100)supported by the Science and the Technology Research Key Project of High School of Hebei Province,China+1 种基金Project(LJRC013)supported by the University Innovation Team of Hebei Province Leading Talent Cultivation,ChinaProject(16LGY015)supported by the Basic Research Special Breeding of Yanshan University,China
文摘The accuracy of present flatness predictive method is limited and it just belongs to software simulation. In order to improve it, a novel flatness predictive model via T-S cloud reasoning network implemented by digital signal processor(DSP) is proposed. First, the combination of genetic algorithm(GA) and simulated annealing algorithm(SAA) is put forward, called GA-SA algorithm, which can make full use of the global search ability of GA and local search ability of SA. Later, based on T-S cloud reasoning neural network, flatness predictive model is designed in DSP. And it is applied to 900 HC reversible cold rolling mill. Experimental results demonstrate that the flatness predictive model via T-S cloud reasoning network can run on the hardware DSP TMS320 F2812 with high accuracy and robustness by using GA-SA algorithm to optimize the model parameter.
基金Project(20040311890) supported by the Science and Technology Development Foundation of University of Science and Technology Beijing
文摘The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations.A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control.In comparison with the conventional backup and work roll contours configuration,the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls(ASR) and varying contact backup rolls(VCR).A better strip profile and flatness quality,an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.
基金Project(50675186) supported by the National Natural Science Foundation of China
文摘To overcome the disadvantage that the standard least squares support vector regression(LS-SVR) algorithm is not suitable to multiple-input multiple-output(MIMO) system modelling directly,an improved LS-SVR algorithm which was defined as multi-output least squares support vector regression(MLSSVR) was put forward by adding samples' absolute errors in objective function and applied to flatness intelligent control.To solve the poor-precision problem of the control scheme based on effective matrix in flatness control,the predictive control was introduced into the control system and the effective matrix-predictive flatness control method was proposed by combining the merits of the two methods.Simulation experiment was conducted on 900HC reversible cold roll.The performance of effective matrix method and the effective matrix-predictive control method were compared,and the results demonstrate the validity of the effective matrix-predictive control method.
基金Project(50876016) support by the National Natural Science Foundation of China
文摘An innovative flat heat pipe radiator was put forward, and it has the features of high efficiency of heat dissipation, compact construction, low thermal resistance, light weight, low cost, and anti-dust-deposition. The thermal analysis of the flat heat pipe radiator for cooling high-power light emitting diode （LED） array was conducted. The thermal characteristics of the flat heat pipe radiator under the different heat loads and incline angles were investigated experimentally in natural convection. An electro-thermal conversion method was used to measure the junction temperature of the LED chips. It is found that the integral temperature distribution of the flat heat pipe radiator is reasonable and uniform. The total thermal resistance of the flat heat pipe radiator varies in the range of 0.38-0.45 K/W. The junction temperatures of LED chips with the flat heat pipe radiator and with the aluminum board at the same forward current of 0.35 A are 52.5 and 75.2 ℃, respectively.
基金Supported by National Key Technology R&D Program(2006BAD11A05)National Soybean Industry Technology System
文摘Based on the study on cultivation models of soybean narrow-row-flat-dense planting under the conditions of different between-row spacing and inter-plant spacing by using the comparison field experiment, and technical studies of the contour following the seeder unit, the anti-block, the lateral and stratified the deep fertilizing, according to the design ideas of planting units integration and variable between-row spacing from 30 to 45 cm, the 2BZJ-3/4 precision planter matched with 18-32 hp tractors has been developed for the popularization of the narrow-row-flat-dense planting soybean technique by means of Virtual Prototyping （VP） technology.
文摘Two fundamental hypotheses of special relativistic gravitational theory are: (1) the equivalence of gravitational mass and inertial mass, (2) the equation of the gravitational tensor potential in linear approximation. Main results: (1) the values of the planetary perihelion shill, and the angle of deflection of light are the same as those of general relativity. The value of the red shill is consistent with the experiment. One cannot use these experimental values to judge whether space-time is curved. (2) In GP-B experiment, the gyroscope will be acted on by the additional gravitational fields due to the Earth's spin (S) and the orbital motion of satellite (L). The average precession rates are , where β and δ are the gyroscope's polar angles, (S) and (G) designate values deduced from special and general relativity, respectively. The GP-B experiment is the first one to judge whether space-time is flat.
基金Project(2011ZX05013-006)supported by the National Science and Technology Project of China
文摘As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern adaptability.Through experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow curve.The results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well pattern.With the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational increase.Under the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.
文摘An investigation has been carried out to compare th e cutting performance and tool life evaluation of high speed steel broach samp les. The comparison has been done between conventional M2 and Anti-Segregation Process (ASP) ASP53 and ASP30 high speed steel broach samples. The ASP53 was a development material. The cutting performance was evaluated by measuring the c utting forces and calculating the specific cutting energy, an indicator of cutti ng performance. As the roughness of the machined surface is an important criter ion in the evaluation of performance of a tool, the surface roughness of the workpiece was studied as a function of undeformed chip thickness. The workpiec e material was 150M36 alloy steel used in manufacture of automobile engines. Th e performance tests were conducted at two cutting speeds, which were 0 7 m/min and 10.5 m/min respectively. This allowed a better understanding of the effect of cutting speed on tool performance. The wear tests were performed at a cuttin g speed on 10.5 m/min. The cutting edges of ASP broach samples were finer compared to that of M2. Ther e was no practical difference in the cutting forces and the specific cutting ene rgy while cutting with MS, ASP30 and ASP53 broach samples. The ASP30 and ASP53 tools have a better surface roughness on the machined surface than that of M2 at both cutting speeds. The ASP30 gave 2.25 times the life and an improved surfac e finish compared to M2 steel. The ASP53 gave 1.3 times the life of M2 steel. These results should prove useful to the tool designer and manufacturing enginee r.
基金Project Supported by National Natural Science Foundation of China（90510014 ）.
文摘The influence of sand dust on discharge of external insulation has caused widespread concern.At present,the research results show wind-sand electricity has a remarkable effect on the discharge characteristics of insulator and has little influence on the discharge characteristics of air gap.The flashover of insulator strings occurs along the insulator surface and air gaps,and the sand dust deposited on the insulator surface may affect the flashover characteristics of insulator strings.This paper studies the flashover characteristics of flat plate model under DC voltage in wind-sand condition.The experimental results show that under positive polarity voltage,the flashover voltage of the flat plate model has a maximum value,while under negative polarity voltage,the flashover voltage of the flat plate model has a minimum value with a certain degree of sand dust deposition.The wind or sand in sand-dust weather has an important effect on the flashover characteristics of the flat plate model.In certain variation range of electric charge,electric charge of sand dust has little effect on the flashover voltage of flat plate model under DC voltage.The deposition of sand has significant influence on the flashover process of flat plate model,which is related to the deposition density and moisture content of sand particle.
基金supported by the"100 Projects"of Creative Research for the Undergraduates of Nankai University under Grant(BX6-224)
文摘A novel all-fibre flat-top comb filter based on a high birefringence photonic crystal fibre loop mirror is proposed and demonstrated. We simulate theoretically its output spectra and experimentally realize a flat-top output with a high extinction ratio. Compared to filters consisting of the conventional Panda polarization maintaining fibre, filters based on a high birefringence photonic crystal fibre loop mirror have better temperature stability. This kind of filter can be expected to be used widely in Wavelength-division-multiplexing(WDM) systems in the future.
