The key technology of semi-continuous conveyor system decides the successful using of this system. The key technology includes optimal initial building depth of this system,the crusher moving step and the layout of co...The key technology of semi-continuous conveyor system decides the successful using of this system. The key technology includes optimal initial building depth of this system,the crusher moving step and the layout of conveyor system are studied, and their calculating models are built up.展开更多
Belt conveyors are extensively utilized in mining and power industries.In a typical coal mine conveyor system,coal is transported over distances exceeding 2 km,involving more than 20000 idlers,which far exceeds a reas...Belt conveyors are extensively utilized in mining and power industries.In a typical coal mine conveyor system,coal is transported over distances exceeding 2 km,involving more than 20000 idlers,which far exceeds a reasonable manual inspection capacity.Given that idlers typically have a lifespan of 1-2 years,there is an urgent need for a rapid,cost-effective,and intelligent safety monitoring system.However,current embedded systems face prohibitive replacement costs,while conventional monitoring technologies suffer from inefficiency at low rotational speeds and lack systematic structural optimization frameworks for diverse idler types and parameters.To address these challenges,this paper introduces an integrated,on-site detachable self-powered idler condition monitoring system(ICMS).This system combines energy harvesting based on the magnetic modulation technology with wireless condition monitoring capabilities.Specifically,it develops a data-driven model integrating convolutional neural networks(CNNs) with genetic algorithms(GAs).The conventional testing results show that the data-driven model not only significantly accelerates the parameter response time,but also achieves a prediction accuracy of 92.95%.The in-situ experiments conducted in coal mines demonstrate the system's reliability and monitoring functionality under both no-load and fullload conditions.This research provides an innovative self-powered condition monitoring solution and develops an efficient data-driven model,offering feasible online monitoring approaches for smart mine construction.展开更多
A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based...A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the vari-able-frequency-control(VFC) method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three-Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.展开更多
Based on the real time measurement of the width of coal flow, the method for measuring the width and the relative position of coal flow on a conveyor-belt by image processing was presented. A feeding control system of...Based on the real time measurement of the width of coal flow, the method for measuring the width and the relative position of coal flow on a conveyor-belt by image processing was presented. A feeding control system of conveyor-belt was proposed using a fuzzy controller. This control system consists of CCD camera, universal image sampling system, control network and executor. The result shows that the algorithm used in the image processing is simple and efficient, and the measuring error of width is less than 4%.展开更多
Belt conveyors are prone to problems suchas conveyor belt deviation during operation.The main correction method is to adjust the angle of the roller frame,but the current adjustment is mostly manual.In order to solve ...Belt conveyors are prone to problems suchas conveyor belt deviation during operation.The main correction method is to adjust the angle of the roller frame,but the current adjustment is mostly manual.In order to solve the problem of low equipment transportation efficiency and low safety causedby conveyor belt deviation,a detection mechanism that can effectively detect conveyor belt deviation parameters is designed,and the working condition information is accurately transmitted to the PLC controller.If an abnormality is found,the designed correction device will correct the deviation,effectively ensuring the reliable and stable operation of the belt conveyor.展开更多
This review paper presents an in-depth investigation of the modeling techniques used to study conveyor belt dryers.These techniques are classified into four categories:theoretical modeling,computational fluid dynamics...This review paper presents an in-depth investigation of the modeling techniques used to study conveyor belt dryers.These techniques are classified into four categories:theoretical modeling,computational fluid dynamics(CFD),empirical,and performance under different control strategies.Within the theoretical and CFD categories,the models are further classified as transient and steady state,as well as one-dimensional,two-dimensional,and three-dimensional.The empirical approach involves conducting experimental studies to collect moisture ratio data during the drying process and comparing it with empirical models.The methods of control are divided into classical and advanced controllers,with classical controllers including proportional-integral(PI),proportional-integral-derivative(PID),and quantitative feedback theory(QFT)controllers.Advanced controllers consist of artificial intelligence-based controllers,such as artificial neural networks(ANN),adaptive neuro-fuzzy inference systems(ANFIS),nonlinear autoregressive exogenous(NARX)models,model predictive control(MPC),and soft sensors.This review elucidated the methodologies and software employed for each modeling technique,as well as their prospective utility in industrial contexts.The utilization of theoretical and CFD methodologies is advantageous in forecasting the dynamics of complex systems.Conversely,empirical techniques serve the purpose of validating theoretical models and procuring data to facilitate model refinement.Controllers play a crucial role in the optimization of the drying process and the attainment of desired outputs.展开更多
Aqueous ion storage systems have motivated great interest by virtue of low reduction,high eco-sustainability and safety.Among various cathode candidates,transition metal compounds are featured with easy dissolution in...Aqueous ion storage systems have motivated great interest by virtue of low reduction,high eco-sustainability and safety.Among various cathode candidates,transition metal compounds are featured with easy dissolution in aqueous solutions and inferior conductivity,which severely hinder their application.Herein,advantages are taken of the“conveyor effect”of conjugated polyaniline to prepare an oxygen defective tungstate-linked polyaniline(O_(d)-WOP)material with chrysanthemum-like microstructure.By virtue of the high electronic conductivity derived from conductive conjugated polyaniline skeleton,unbalanced charge distribution triggered by the defective structure,and reversibly rapid ion(de)intercalation benefited from the open framework with porous chrysanthemum-like microstructure,it delivers outstanding rate capability with a maximum specific capacity of 162.2 mAh g^(-1)and great cycle stability for storing NH_(4)^(+).Additionally,it also adopts a high reversible capacity of 140.4 mAh g^(-1)and outstanding cycling performance to store Ca^(2+).Consequently,the assembled O_(d)-WOP//PTCDI flexible aqueous ammonium ion batteries and calcium ion batteries exhibit superior capacities,energy densities and flexibilities.O_(d)-WOP achieves the NH_(4)^(+) and Ca^(2+)storage capability by interacting with them through hydrogen and ionic bonds,respectively.The deep insight from this work sheds light upon a novel strategy to excavate greater potential of transition metal compounds for aqueous ion batteries.展开更多
The oil film clutch, which is superior in speed adjustment, is capable of being used in the belt conveyor to carry out soft start operation. According to running properties of both belt conveyor and oil film clutch...The oil film clutch, which is superior in speed adjustment, is capable of being used in the belt conveyor to carry out soft start operation. According to running properties of both belt conveyor and oil film clutch, equations that are used to decide the lubricating oil flow and the number of oil films (i.e. the number of rotating and stationary plates) are deduced theoretically. Also key parameters are provided for the design of the hydraulic system. All these together provide the theoretical basis for the soft start design of the belt conveyor and references for the application of the oil film clutch in similar fields.展开更多
In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-Pit Crushing and Conveying(IPCC) systems have been advanced as offering a real alternative to co...In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-Pit Crushing and Conveying(IPCC) systems have been advanced as offering a real alternative to conventional truck haulage systems. The implementation of IPCC systems in hard rock operations in open pit mines however requires different and more comprehensive planning approaches in order to adequately reflect the practical aspects associated with these. This paper investigates the impact that these approaches may have on the implementation of IPCC systems on a basic metalliferous deposit amenable to open pit exploitation. A strategic life of mine plan to provide numerous economic indicators for each approach is analyzed and compared to traditional truck haulage systems. The mine planning and evaluation process highlights the increased overall resource recovery that may accompany the use of IPCC systems. This investigation also provides insights into the issues associated with IPCC and the scale and type of operation and orebody that is likely to provide a feasible alternative to truck haulage.展开更多
Considering the control difficulties of a hydro-viscous trol algorithm was derived. A fuzzy-immune PID controller was soft start （HVSS） device of a belt conveyor, a fuzzy-immune con- designed based on immune feedbac...Considering the control difficulties of a hydro-viscous trol algorithm was derived. A fuzzy-immune PID controller was soft start （HVSS） device of a belt conveyor, a fuzzy-immune con- designed based on immune feedback regulations and adaptability of the fuzzy logic inference. Using MATLAB software, we simulated the controller and compared the HVSS device with a conven- tional PID controller and a fuzzy PID controller. The simulation results show that the controller is not only very reliable as a PID controller, robust and requires only a short adjustment time of fuzzy control, but possesses also capacity of global optimization of the immune algorithm. To verify our theoretical analysis and simulation, a HVSS test-bed was developed. The experimental results demonstrate that the fuzzy-immune PID controller managed to start the belt conveyor softly and to follow an S-shaped curve while the output speed correctly followed the preset speed with only small fluctuations in speed.展开更多
The mechanism of a hydro-viscous soft start is of great importance in the design of a hydro-viscous clutch and its control system. To explain the mechanism of a hydro-viscous soft start, the startup process of a belt ...The mechanism of a hydro-viscous soft start is of great importance in the design of a hydro-viscous clutch and its control system. To explain the mechanism of a hydro-viscous soft start, the startup process of a belt conveyor was numerically analyzed with the modified Reynolds equation, an energy equation and a temperature-viscosity equation. The effect of temperature and grooves of the friction disk surface on torque transfer and load capacity of the oil film have also been analyzed. The results show that 1) the grooves are the basis of forming dynamic pressure but they may reduce the capacity of torque transfer to a certain extent, 2) during the startup process, temperature has little effect on torque transfer and load capacity and the variation in load capacity of the oil film is very small, indicating that it is preferable to use the flow rate as a control object than the pressure of the feed cylinder. The results have been verified by an experiment.展开更多
According to the equivalent view for the terminal current-voltage constraint relationship between pathological elements and the various second-generation current-controlled convegors （CCCIIs）, four patholo- gical mo...According to the equivalent view for the terminal current-voltage constraint relationship between pathological elements and the various second-generation current-controlled convegors （CCCIIs）, four patholo- gical models for the CCCII are first derived by means of the nodal admittance matrix expansion in this paper. Moreover, 48 new pathological models for the modified CCCII are also synthesized. The derived pathological models for the various CCCIIs are expected to be useful in circuit analysis and synthesis.展开更多
By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing ...By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing four CCCIIs and three grounded capacitors is synthesized. Thirty-two Colpitts oscillators using CCCIIs are obtained in all. By using canonical number of components, the circuits can be easily integrated and the oscillation criterion and the oscillation frequency can be independently and electronically tuned by tuning bias currents of the CCCIIs. The paper-and-pencil analysis and Pspice simulation results have been included to support the synthesis method.展开更多
In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance wit...In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance with the pathological models of the operational transconductance amplifier(OTA)and second generation current-controlled conveyor(CCCII),the multiplefeedback filter based on OTAs and CCCIIs are respectively synthesized by the NAM expansion method.The filter employing three OTAs has eight equivalent realizations and the filter employing three CCCIIs has 16 equivalent realizations.24 different forms of the current-mode filters are synthesized in all.fo and Q of the synthesized filters can be tuned by tuning bias currents of the active elements.The hand analysis and computer analysis are included to support the method to be utilized.展开更多
Continuous and semi-continuous mining technology has become the main trend of modern surface mines in the world. According to the deposit characteristics of coal basin in China and Chinese situation,this paper discuss...Continuous and semi-continuous mining technology has become the main trend of modern surface mines in the world. According to the deposit characteristics of coal basin in China and Chinese situation,this paper discussed the new semi-continuous technology── shovel - transfer wagon-belt conveyor and its application prospect in large surface coal mines in China.展开更多
The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dyn...The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and rheologicat constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.展开更多
The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual dis...The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual distance of the scraper conveyor and the theoretical moving distance.As a result,the scraper conveyor cannot obtain the straightness requirement.Therefore,the movement law of the floating connecting mechanism between the hydraulic support and scraper conveyor is analyzed and programmed into the Unity3D to realize accurate pushing of the scraper conveyor via hydraulic support.The Coal Seam?Equipment Joint Virtual Straightening System is established,and a straightening method based on the motion law of a floating connection is proposed as the default method of the system.In addition,a straightening simulation of the scraper conveyor was performed on a complex coal seam floor,the results demonstrate that the average straightening error of the scraper conveyor is within 2-8 mm,and is in direct proportion to the fluctuation of the coal seam floor in the strike of the seam with high accuracy,the straightness of scraper conveyor is more affected by the subsidence terrain during straightening than by the bulge terrain.And some conclusions are verified by experiment.Based on the verification of the relevant conclusions,a comparison and analysis of Longwall Automation Steering Committee(LASC)straightening technology and default straightening method in the simulation system shows that the straightness accuracy of LASC straightening technology under complex floor conditions is slightly less than that of the default straightening method in the proposed system.展开更多
文摘The key technology of semi-continuous conveyor system decides the successful using of this system. The key technology includes optimal initial building depth of this system,the crusher moving step and the layout of conveyor system are studied, and their calculating models are built up.
基金supported by the National Natural Science Foundation of China(Nos.12172248,12302022,12021002,and 12132010)the Tianjin Research Program of Application Foundation and Advanced Technology of China(No.23JCZDJC00950)。
文摘Belt conveyors are extensively utilized in mining and power industries.In a typical coal mine conveyor system,coal is transported over distances exceeding 2 km,involving more than 20000 idlers,which far exceeds a reasonable manual inspection capacity.Given that idlers typically have a lifespan of 1-2 years,there is an urgent need for a rapid,cost-effective,and intelligent safety monitoring system.However,current embedded systems face prohibitive replacement costs,while conventional monitoring technologies suffer from inefficiency at low rotational speeds and lack systematic structural optimization frameworks for diverse idler types and parameters.To address these challenges,this paper introduces an integrated,on-site detachable self-powered idler condition monitoring system(ICMS).This system combines energy harvesting based on the magnetic modulation technology with wireless condition monitoring capabilities.Specifically,it develops a data-driven model integrating convolutional neural networks(CNNs) with genetic algorithms(GAs).The conventional testing results show that the data-driven model not only significantly accelerates the parameter response time,but also achieves a prediction accuracy of 92.95%.The in-situ experiments conducted in coal mines demonstrate the system's reliability and monitoring functionality under both no-load and fullload conditions.This research provides an innovative self-powered condition monitoring solution and develops an efficient data-driven model,offering feasible online monitoring approaches for smart mine construction.
文摘A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the vari-able-frequency-control(VFC) method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three-Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.
文摘Based on the real time measurement of the width of coal flow, the method for measuring the width and the relative position of coal flow on a conveyor-belt by image processing was presented. A feeding control system of conveyor-belt was proposed using a fuzzy controller. This control system consists of CCD camera, universal image sampling system, control network and executor. The result shows that the algorithm used in the image processing is simple and efficient, and the measuring error of width is less than 4%.
基金Yingkou Institute of Technology school-level scientificresearch project(Grant:ZDIL202302).
文摘Belt conveyors are prone to problems suchas conveyor belt deviation during operation.The main correction method is to adjust the angle of the roller frame,but the current adjustment is mostly manual.In order to solve the problem of low equipment transportation efficiency and low safety causedby conveyor belt deviation,a detection mechanism that can effectively detect conveyor belt deviation parameters is designed,and the working condition information is accurately transmitted to the PLC controller.If an abnormality is found,the designed correction device will correct the deviation,effectively ensuring the reliable and stable operation of the belt conveyor.
基金supported by the AmericanUniversity in Cairo,Egypt.
文摘This review paper presents an in-depth investigation of the modeling techniques used to study conveyor belt dryers.These techniques are classified into four categories:theoretical modeling,computational fluid dynamics(CFD),empirical,and performance under different control strategies.Within the theoretical and CFD categories,the models are further classified as transient and steady state,as well as one-dimensional,two-dimensional,and three-dimensional.The empirical approach involves conducting experimental studies to collect moisture ratio data during the drying process and comparing it with empirical models.The methods of control are divided into classical and advanced controllers,with classical controllers including proportional-integral(PI),proportional-integral-derivative(PID),and quantitative feedback theory(QFT)controllers.Advanced controllers consist of artificial intelligence-based controllers,such as artificial neural networks(ANN),adaptive neuro-fuzzy inference systems(ANFIS),nonlinear autoregressive exogenous(NARX)models,model predictive control(MPC),and soft sensors.This review elucidated the methodologies and software employed for each modeling technique,as well as their prospective utility in industrial contexts.The utilization of theoretical and CFD methodologies is advantageous in forecasting the dynamics of complex systems.Conversely,empirical techniques serve the purpose of validating theoretical models and procuring data to facilitate model refinement.Controllers play a crucial role in the optimization of the drying process and the attainment of desired outputs.
基金supported by the Natural Science Foundation of Liaoning Province(2023-MS-115).
文摘Aqueous ion storage systems have motivated great interest by virtue of low reduction,high eco-sustainability and safety.Among various cathode candidates,transition metal compounds are featured with easy dissolution in aqueous solutions and inferior conductivity,which severely hinder their application.Herein,advantages are taken of the“conveyor effect”of conjugated polyaniline to prepare an oxygen defective tungstate-linked polyaniline(O_(d)-WOP)material with chrysanthemum-like microstructure.By virtue of the high electronic conductivity derived from conductive conjugated polyaniline skeleton,unbalanced charge distribution triggered by the defective structure,and reversibly rapid ion(de)intercalation benefited from the open framework with porous chrysanthemum-like microstructure,it delivers outstanding rate capability with a maximum specific capacity of 162.2 mAh g^(-1)and great cycle stability for storing NH_(4)^(+).Additionally,it also adopts a high reversible capacity of 140.4 mAh g^(-1)and outstanding cycling performance to store Ca^(2+).Consequently,the assembled O_(d)-WOP//PTCDI flexible aqueous ammonium ion batteries and calcium ion batteries exhibit superior capacities,energy densities and flexibilities.O_(d)-WOP achieves the NH_(4)^(+) and Ca^(2+)storage capability by interacting with them through hydrogen and ionic bonds,respectively.The deep insight from this work sheds light upon a novel strategy to excavate greater potential of transition metal compounds for aqueous ion batteries.
文摘The oil film clutch, which is superior in speed adjustment, is capable of being used in the belt conveyor to carry out soft start operation. According to running properties of both belt conveyor and oil film clutch, equations that are used to decide the lubricating oil flow and the number of oil films (i.e. the number of rotating and stationary plates) are deduced theoretically. Also key parameters are provided for the design of the hydraulic system. All these together provide the theoretical basis for the soft start design of the belt conveyor and references for the application of the oil film clutch in similar fields.
文摘In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-Pit Crushing and Conveying(IPCC) systems have been advanced as offering a real alternative to conventional truck haulage systems. The implementation of IPCC systems in hard rock operations in open pit mines however requires different and more comprehensive planning approaches in order to adequately reflect the practical aspects associated with these. This paper investigates the impact that these approaches may have on the implementation of IPCC systems on a basic metalliferous deposit amenable to open pit exploitation. A strategic life of mine plan to provide numerous economic indicators for each approach is analyzed and compared to traditional truck haulage systems. The mine planning and evaluation process highlights the increased overall resource recovery that may accompany the use of IPCC systems. This investigation also provides insights into the issues associated with IPCC and the scale and type of operation and orebody that is likely to provide a feasible alternative to truck haulage.
文摘Considering the control difficulties of a hydro-viscous trol algorithm was derived. A fuzzy-immune PID controller was soft start （HVSS） device of a belt conveyor, a fuzzy-immune con- designed based on immune feedback regulations and adaptability of the fuzzy logic inference. Using MATLAB software, we simulated the controller and compared the HVSS device with a conven- tional PID controller and a fuzzy PID controller. The simulation results show that the controller is not only very reliable as a PID controller, robust and requires only a short adjustment time of fuzzy control, but possesses also capacity of global optimization of the immune algorithm. To verify our theoretical analysis and simulation, a HVSS test-bed was developed. The experimental results demonstrate that the fuzzy-immune PID controller managed to start the belt conveyor softly and to follow an S-shaped curve while the output speed correctly followed the preset speed with only small fluctuations in speed.
文摘The mechanism of a hydro-viscous soft start is of great importance in the design of a hydro-viscous clutch and its control system. To explain the mechanism of a hydro-viscous soft start, the startup process of a belt conveyor was numerically analyzed with the modified Reynolds equation, an energy equation and a temperature-viscosity equation. The effect of temperature and grooves of the friction disk surface on torque transfer and load capacity of the oil film have also been analyzed. The results show that 1) the grooves are the basis of forming dynamic pressure but they may reduce the capacity of torque transfer to a certain extent, 2) during the startup process, temperature has little effect on torque transfer and load capacity and the variation in load capacity of the oil film is very small, indicating that it is preferable to use the flow rate as a control object than the pressure of the feed cylinder. The results have been verified by an experiment.
基金supported by the Natural Science Foundation of Shaanxi Province under Grant No.2017JM6087
文摘According to the equivalent view for the terminal current-voltage constraint relationship between pathological elements and the various second-generation current-controlled convegors （CCCIIs）, four patholo- gical models for the CCCII are first derived by means of the nodal admittance matrix expansion in this paper. Moreover, 48 new pathological models for the modified CCCII are also synthesized. The derived pathological models for the various CCCIIs are expected to be useful in circuit analysis and synthesis.
基金Supported by the Shaanxi Provincial Key Research and Development Program,China(2018NY-158)
文摘By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing four CCCIIs and three grounded capacitors is synthesized. Thirty-two Colpitts oscillators using CCCIIs are obtained in all. By using canonical number of components, the circuits can be easily integrated and the oscillation criterion and the oscillation frequency can be independently and electronically tuned by tuning bias currents of the CCCIIs. The paper-and-pencil analysis and Pspice simulation results have been included to support the synthesis method.
基金Supported by the Shaanxi Provincial Key Research and Development Program,China(2018NY-158).
文摘In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance with the pathological models of the operational transconductance amplifier(OTA)and second generation current-controlled conveyor(CCCII),the multiplefeedback filter based on OTAs and CCCIIs are respectively synthesized by the NAM expansion method.The filter employing three OTAs has eight equivalent realizations and the filter employing three CCCIIs has 16 equivalent realizations.24 different forms of the current-mode filters are synthesized in all.fo and Q of the synthesized filters can be tuned by tuning bias currents of the active elements.The hand analysis and computer analysis are included to support the method to be utilized.
文摘Continuous and semi-continuous mining technology has become the main trend of modern surface mines in the world. According to the deposit characteristics of coal basin in China and Chinese situation,this paper discussed the new semi-continuous technology── shovel - transfer wagon-belt conveyor and its application prospect in large surface coal mines in China.
文摘The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and rheologicat constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These included longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile load was the main factor influencing longitudinal vibrations.
基金This research was supported by the Project funded by National Natural Science Foundation of China(Grant No.52004174)China Postdoctoral Science Foundation(No.2019M651081)+2 种基金the Key Research and Development Program of Shanxi(201903D121141)the Natural Science Foundation of Shanxi Province(201901D211022)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shan Xi(No.2019L0305).
文摘The movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement;thus,when the hydraulic support pushes the scraper conveyor,there is an error between the actual distance of the scraper conveyor and the theoretical moving distance.As a result,the scraper conveyor cannot obtain the straightness requirement.Therefore,the movement law of the floating connecting mechanism between the hydraulic support and scraper conveyor is analyzed and programmed into the Unity3D to realize accurate pushing of the scraper conveyor via hydraulic support.The Coal Seam?Equipment Joint Virtual Straightening System is established,and a straightening method based on the motion law of a floating connection is proposed as the default method of the system.In addition,a straightening simulation of the scraper conveyor was performed on a complex coal seam floor,the results demonstrate that the average straightening error of the scraper conveyor is within 2-8 mm,and is in direct proportion to the fluctuation of the coal seam floor in the strike of the seam with high accuracy,the straightness of scraper conveyor is more affected by the subsidence terrain during straightening than by the bulge terrain.And some conclusions are verified by experiment.Based on the verification of the relevant conclusions,a comparison and analysis of Longwall Automation Steering Committee(LASC)straightening technology and default straightening method in the simulation system shows that the straightness accuracy of LASC straightening technology under complex floor conditions is slightly less than that of the default straightening method in the proposed system.
