The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the buildi...The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.展开更多
Off line programming provides an essential link between CAD and CAM, whose development will result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is one of...Off line programming provides an essential link between CAD and CAM, whose development will result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is one of the most typical workcells. The inverse kinematics of robot and positioner is the foundation of the off line programming system. The previous researchers only focused on a special solution of the positioner inverse kinematics, which is the solution at down hand welding position. In this paper, we introduce a method for representing welding position. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented, and an approach to find the unique solution of the inverse kinematics is discussed. The simulation experiment results show that the general algorithm can improve the ability of robotic arc welding off line programming system to program all types of welding positions.展开更多
The development of the tilting train can contribute to solve the economic burden and enhance the transportation means of areas that did not share the benefits of the high speed railway. But the dynamic behavior caused...The development of the tilting train can contribute to solve the economic burden and enhance the transportation means of areas that did not share the benefits of the high speed railway. But the dynamic behavior caused by the interaction between the train and the track as well as the environmental vibrations along the railway should be evaluated to secure the safety of the train and riding comfort. In this paper a study on the characteristics for ground vibration due to the tilting train travelling in the conventional line are carried out. The transmitted load into the ground is computed through a study on the interrelation between the tilting car and the line. This load is applied into the numerical model which is one for the analysis of ground vibration due to the travelling tilting car. The far fields on the numerical model are formed by the absorbing boundary using dashpot, one of the most widely used absorbing boundary in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by travelling tilting car is performed. From the analysis, it is shown that the transferred load due to the tilting train is larger than that of the conventional train.展开更多
By using tilting carbodies, train can negotiate at a higher speed withoutreducing the passenger's ride quality. This is a good method to allow a significant increase inspeed at existing track to improve the railwa...By using tilting carbodies, train can negotiate at a higher speed withoutreducing the passenger's ride quality. This is a good method to allow a significant increase inspeed at existing track to improve the railway transportation capability, and to enhance thecompetition ability of railways with other transportation systems. With the increase of the curvenegotiation speed, the wheel-rail lateral forces and wheel-rail wear of the tilting train willincrease. The self-steering radial bogie is an effective way to solve the problem. The dynamic modelof the tilting passenger car with self-steering bogies is established in detail, and the curvingperformance of the car is investigated.展开更多
Let A be a finite dimensional k-algebra and T be a supportτ-tilting right A-module.In this note,we give lower and upper bounds for the global dimension of the endomorphism algebra End_(A)(T)under some mild conditions...Let A be a finite dimensional k-algebra and T be a supportτ-tilting right A-module.In this note,we give lower and upper bounds for the global dimension of the endomorphism algebra End_(A)(T)under some mild conditions.Finally,we give some examples to illustrate that both the upper and lower bounds can be reached.展开更多
Radio resources must be wisely managed, in wireless communication systems, when implementing different multiple access techniques. This perspective is pivotal since the variations in propagation channel are very fast ...Radio resources must be wisely managed, in wireless communication systems, when implementing different multiple access techniques. This perspective is pivotal since the variations in propagation channel are very fast and the system is highly complex due to random and unpredictable movement of mobile users continuously. The complexity in the cellular system periodically contributes to different interference levels, high or low, resulting in the degradation of the system capacity. Transmitter power control is an efficient technique to mitigate the effect of interference under fading conditions, combat the Near-Far problem and conserve the battery life. Several remedial measures—like space diversity, frequency diversity, route diversity, increase in antenna height, antenna tilting, etc.—have been tried by many operators to overcome the debilitating effect of multipath fading in fixed line-of-sight microwave and mobile communication links. Among these remedial measures, diversity techniques have been extensively studied in terms of improvement factor, whereas the concept of antenna tilting is relatively less explored compared with other remedial measures. In this study, the effect of antenna tilting on fixed and mobile communication links is investigated to find out the optimum tilting angles in terms of design parameters, as well as on quality of service (QoS). The paper established that a deviation of more than 1.5o in antenna elevation angle would impact on QoS requirements and seriously affect the quality of signal to be received by the mobile systems.展开更多
The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 (for the simple cubic structure where no octahedral tilting exists anymore) are studied using the density functional theory withi...The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 (for the simple cubic structure where no octahedral tilting exists anymore) are studied using the density functional theory within the generalized gradient approximation as well as taking into account the on-site Coulomb repulsive interaction. The total energy, the spin magnetic moment, the band structure and the density of states are calculated. The optimization of the lattice constants is 8.5173 A, which is in good agreement with the experimental value 8.5180 A. The calculations reveal that Ba2SmNbO6 has a stable ferromagnetic ground state and the spin magnetic moment per molecule is 5.00μB/f.u. which comes mostly from the Sin3+ ion only. By analysis of the band structure, the compound exhibits the direct band gap material and half-metallic ferromagnetic nature with 100% spin-up polarization, which implies potential applications of this new lanthanide compound in magneto-electronic and spintronic devices.展开更多
In this paper, a study on the characteristics and the reduction methods of ground vibration due to the tilting train travelling in the conventional line is carried out. The load transmitted into the ground is computed...In this paper, a study on the characteristics and the reduction methods of ground vibration due to the tilting train travelling in the conventional line is carried out. The load transmitted into the ground is computed considering the interaction between the tilting car and the line. This load is then applied in the numerical model for the analysis of ground vibration due to the travelling tilting car. The far-fields of the numerical model are modeled using the dashpot, as one of the most widely used absorbing boundaries in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by the travelling tilting car and the analysis of the blocking effect of the ground vibration by wave barriers are performed. From the numerical analysis, it is shown that the blocking effect of the trench and the barrier filled with soft material is more effective than that of the barrier filled with hard material.展开更多
-The probabilities P<sub>NCNE</sub> of non-equilibration component of tilting spinmode have been extracted from the experimental fragment anisotropies for thesystems of <sup>16</sup>O+<sup&g...-The probabilities P<sub>NCNE</sub> of non-equilibration component of tilting spinmode have been extracted from the experimental fragment anisotropies for thesystems of <sup>16</sup>O+<sup>232</sup>Th,<sup>19</sup>F+<sup>232</sup>Th,and <sup>16</sup>O+<sup>238</sup>U.It is found that as a function ofB<sub>f</sub>(〈L〉)/T<sub>sad</sub>,the values of P<sub>NCNF</sub> observed experimentally and expected on the ba-sis of fission before equilibration model have opposite trends.展开更多
The kinematics and kinetics of the tilting mechanism of railway passenger cars are studied. The parameters of the mechanism are given. The motions of the actuator, the center of gravity of the carbody and the center o...The kinematics and kinetics of the tilting mechanism of railway passenger cars are studied. The parameters of the mechanism are given. The motions of the actuator, the center of gravity of the carbody and the center of coupler are calculated. Finally, the maximum driving force, output power and velocity of the actuator are discussed in detail.展开更多
In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which ...In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.展开更多
The impedance element in distance protection equipment in the outgoing line of a wind park(WP)may be heavily affected by the fault response of the WP.During resistive grid faults,relay over-reach(or under-reach)may ma...The impedance element in distance protection equipment in the outgoing line of a wind park(WP)may be heavily affected by the fault response of the WP.During resistive grid faults,relay over-reach(or under-reach)may manifest,depending on the fault current regulating requirements in the specific grid code deployed in WP and the fault conditions.Aiming at potential solution,i.e.the existing zone 1(fast tripping zone,non-delayed)top-line tilting(Z-1-TLT)function in modern numerical relays,this paper first assesses its adaptability under the WP integrated background.Combining the principle of Z-1-TLT itself and fault modeling to the WP,an improved Z-1-TLT scheme is developed,which can actively compensate for the possible relay overreach or under-reach during resistive faults,utilizing relay side fault quantities only.Aiming at the needless action of the new Z-1-TLT scheme against certain faults,malfunction risk area detection and dead zone detection are introduced as auxiliary criteria to optimize protective efficiency.Simulation results prove the improved Z-1-TLT scheme can effectively improve reliability of distance protection deployed in the WP outgoing line.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.62172242,51901152)Industry University Cooperation Education Program of the Ministry of Education(No.2020021680113)Shanxi Scholarship Council of China.
文摘The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.
基金ThispaperissupportedbyNationalNatureScienceFoundation (No .5 96 35 16 0 )AdvancedUniversityDoctoralSubjectFoundation (No .980 2 1311)
文摘Off line programming provides an essential link between CAD and CAM, whose development will result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is one of the most typical workcells. The inverse kinematics of robot and positioner is the foundation of the off line programming system. The previous researchers only focused on a special solution of the positioner inverse kinematics, which is the solution at down hand welding position. In this paper, we introduce a method for representing welding position. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented, and an approach to find the unique solution of the inverse kinematics is discussed. The simulation experiment results show that the general algorithm can improve the ability of robotic arc welding off line programming system to program all types of welding positions.
文摘The development of the tilting train can contribute to solve the economic burden and enhance the transportation means of areas that did not share the benefits of the high speed railway. But the dynamic behavior caused by the interaction between the train and the track as well as the environmental vibrations along the railway should be evaluated to secure the safety of the train and riding comfort. In this paper a study on the characteristics for ground vibration due to the tilting train travelling in the conventional line are carried out. The transmitted load into the ground is computed through a study on the interrelation between the tilting car and the line. This load is applied into the numerical model which is one for the analysis of ground vibration due to the travelling tilting car. The far fields on the numerical model are formed by the absorbing boundary using dashpot, one of the most widely used absorbing boundary in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by travelling tilting car is performed. From the analysis, it is shown that the transferred load due to the tilting train is larger than that of the conventional train.
基金This project is supported by Research Foundation of Ministry of Railways of China (No.99J45-B) and National Excellent Doctor Degree Dissertation Foundation of Universities (No.200048).
文摘By using tilting carbodies, train can negotiate at a higher speed withoutreducing the passenger's ride quality. This is a good method to allow a significant increase inspeed at existing track to improve the railway transportation capability, and to enhance thecompetition ability of railways with other transportation systems. With the increase of the curvenegotiation speed, the wheel-rail lateral forces and wheel-rail wear of the tilting train willincrease. The self-steering radial bogie is an effective way to solve the problem. The dynamic modelof the tilting passenger car with self-steering bogies is established in detail, and the curvingperformance of the car is investigated.
基金supported by the National Natural Science Foundation of China(11971255,11901567,12071120)supported by the Hunan Provincial Natural Science Foundation of China(2023JJ30008)the National Natural Science Foundation of China(12371034).
文摘Let A be a finite dimensional k-algebra and T be a supportτ-tilting right A-module.In this note,we give lower and upper bounds for the global dimension of the endomorphism algebra End_(A)(T)under some mild conditions.Finally,we give some examples to illustrate that both the upper and lower bounds can be reached.
文摘Radio resources must be wisely managed, in wireless communication systems, when implementing different multiple access techniques. This perspective is pivotal since the variations in propagation channel are very fast and the system is highly complex due to random and unpredictable movement of mobile users continuously. The complexity in the cellular system periodically contributes to different interference levels, high or low, resulting in the degradation of the system capacity. Transmitter power control is an efficient technique to mitigate the effect of interference under fading conditions, combat the Near-Far problem and conserve the battery life. Several remedial measures—like space diversity, frequency diversity, route diversity, increase in antenna height, antenna tilting, etc.—have been tried by many operators to overcome the debilitating effect of multipath fading in fixed line-of-sight microwave and mobile communication links. Among these remedial measures, diversity techniques have been extensively studied in terms of improvement factor, whereas the concept of antenna tilting is relatively less explored compared with other remedial measures. In this study, the effect of antenna tilting on fixed and mobile communication links is investigated to find out the optimum tilting angles in terms of design parameters, as well as on quality of service (QoS). The paper established that a deviation of more than 1.5o in antenna elevation angle would impact on QoS requirements and seriously affect the quality of signal to be received by the mobile systems.
文摘The structural, magnetic and electronic properties of the double perovskite Ba2SmNbO6 (for the simple cubic structure where no octahedral tilting exists anymore) are studied using the density functional theory within the generalized gradient approximation as well as taking into account the on-site Coulomb repulsive interaction. The total energy, the spin magnetic moment, the band structure and the density of states are calculated. The optimization of the lattice constants is 8.5173 A, which is in good agreement with the experimental value 8.5180 A. The calculations reveal that Ba2SmNbO6 has a stable ferromagnetic ground state and the spin magnetic moment per molecule is 5.00μB/f.u. which comes mostly from the Sin3+ ion only. By analysis of the band structure, the compound exhibits the direct band gap material and half-metallic ferromagnetic nature with 100% spin-up polarization, which implies potential applications of this new lanthanide compound in magneto-electronic and spintronic devices.
文摘In this paper, a study on the characteristics and the reduction methods of ground vibration due to the tilting train travelling in the conventional line is carried out. The load transmitted into the ground is computed considering the interaction between the tilting car and the line. This load is then applied in the numerical model for the analysis of ground vibration due to the travelling tilting car. The far-fields of the numerical model are modeled using the dashpot, as one of the most widely used absorbing boundaries in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by the travelling tilting car and the analysis of the blocking effect of the ground vibration by wave barriers are performed. From the numerical analysis, it is shown that the blocking effect of the trench and the barrier filled with soft material is more effective than that of the barrier filled with hard material.
基金The project supported by the National Natural Science Foundation of China under the contract No.19275067.
文摘-The probabilities P<sub>NCNE</sub> of non-equilibration component of tilting spinmode have been extracted from the experimental fragment anisotropies for thesystems of <sup>16</sup>O+<sup>232</sup>Th,<sup>19</sup>F+<sup>232</sup>Th,and <sup>16</sup>O+<sup>238</sup>U.It is found that as a function ofB<sub>f</sub>(〈L〉)/T<sub>sad</sub>,the values of P<sub>NCNF</sub> observed experimentally and expected on the ba-sis of fission before equilibration model have opposite trends.
文摘The kinematics and kinetics of the tilting mechanism of railway passenger cars are studied. The parameters of the mechanism are given. The motions of the actuator, the center of gravity of the carbody and the center of coupler are calculated. Finally, the maximum driving force, output power and velocity of the actuator are discussed in detail.
文摘In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.
基金This work was supported by the EUDP Project‘Voltage Control and Protection for a Grid towards 100%Power Electronics and Cable Network(COPE)’(EUDP17-I:12561)。
文摘The impedance element in distance protection equipment in the outgoing line of a wind park(WP)may be heavily affected by the fault response of the WP.During resistive grid faults,relay over-reach(or under-reach)may manifest,depending on the fault current regulating requirements in the specific grid code deployed in WP and the fault conditions.Aiming at potential solution,i.e.the existing zone 1(fast tripping zone,non-delayed)top-line tilting(Z-1-TLT)function in modern numerical relays,this paper first assesses its adaptability under the WP integrated background.Combining the principle of Z-1-TLT itself and fault modeling to the WP,an improved Z-1-TLT scheme is developed,which can actively compensate for the possible relay overreach or under-reach during resistive faults,utilizing relay side fault quantities only.Aiming at the needless action of the new Z-1-TLT scheme against certain faults,malfunction risk area detection and dead zone detection are introduced as auxiliary criteria to optimize protective efficiency.Simulation results prove the improved Z-1-TLT scheme can effectively improve reliability of distance protection deployed in the WP outgoing line.