A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated ...A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated into the closed-loop system model, which includes: a model based upon the mean force-velocity (f-v) behaviour; and a model synthesis comprising inherent nonsmooth hysteretic force and the force limiting properties of the MR damper. The vehicle models are analyzed to study the vibration attenuation performance of the MR-damper using the semi-active force tracking PI control algorithm. The simulation results are also presented to demonstrate the influence of the damper nonlinearity, specifically the hysteresis, on the suspension performance. The results show that the proposed control strategy can yield superior vibration attenuation performance of the vehicle suspension actuated by the controllable MR-damper not only in the sprung mass resonance and the ride zones, but also in the vicinity of the wheel-hop. The results further show that the presence of damper hystersis deteriorates the suspension performance.展开更多
Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9F...Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.展开更多
The layered LiNi0.6Co0.2Mn0.2-yMgyO2-zFz（0≤y≤0.12, 0≤z≤0.08） cathode materials were synthesized by combining co-precipitation method and high temperature solid-state reaction, with the help of the ball milling, ...The layered LiNi0.6Co0.2Mn0.2-yMgyO2-zFz（0≤y≤0.12, 0≤z≤0.08） cathode materials were synthesized by combining co-precipitation method and high temperature solid-state reaction, with the help of the ball milling, to investigate the effects of F-Mg doping on LiNi0.6Co0.2Mn0.2O）2. Compared with previous studies, this doping treatment provides substantially improved electrochemical performance in terms of initial coulombic efficiency and cycle performance. The LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 electrode delivers an high capacity retention of 98.6% during the first cycle and a discharge capacity of 189.7 m A·h/g（2.8-4.4 V at 0.2 C）, with the capacity retention of 96.3% after 100 cycles. And electrochemical impedance spectroscopy（EIS） results show that Mg-F co-doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance. It is demonstrated that LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 is a promising cathode material for lithium-ion batteries for excellent electrochemical properties.展开更多
Objective:To observe the effects of electroacupuncture(EA)on uterine prostaglandin F2α(PGF2α),cyclooxygenase 2(COX-2)and nuclear factorκB(NF-κB)in rats with primary dysmenorrhea(PD)and to discuss the possible mech...Objective:To observe the effects of electroacupuncture(EA)on uterine prostaglandin F2α(PGF2α),cyclooxygenase 2(COX-2)and nuclear factorκB(NF-κB)in rats with primary dysmenorrhea(PD)and to discuss the possible mechanism in EA intervening PD.Methods:Forty Sprague-Dawley female rats were randomly divided into a blank group,a model group,an EA group and an ibuprofen group,with 10 rats in each group.The PD model was established using estradiol benzoate combined with oxytocin in the model group,EA group and ibuprofen group.At the same time of modeling,rats in the EA group were given EA at Guanyuan(CV 4)and Sanyinjiao(SP 6)once a day for 20 min each time for 10 consecutive days.Ibuprofen was intragastrically administered once a day for 10 consecutive days in the ibuprofen group.The same amount of normal saline was intragastrically administered once a day for 10 consecutive days in the blank group and model group.The number of writhing of rats in each group within 30 min was compared on the 11th day just after the interventions.The uterine homogenate supernatant was separated and the PGF2αlevel was detected by enzyme-linked immunosorbent assay.Western blot was applied for the detection of the expression levels of COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues.Results:Compared with the blank group,the number of writhing in the model group increased significantly(P<0.01),and the expression levels of PGF2α,COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues were significantly increased(all P<0.01).Compared with the model group,the number of writhing in the EA group and ibuprofen group were significantly reduced(both P<0.01),and the expression levels of PGF2αand COX-2 protein in uterine tissues were significantly reduced(both P<0.01).Compared with the model group,the phospho-NF-κB p65 level in uterine tissues in the EA group was significantly reduced(P<0.01).Compared with the ibuprofen group,the phospho-NF-κB p65 level in the EA group was significantly reduced(P<0.01).Conclusion:The mechanism of EA for PD rats may be related to inhibiting the phosphorylation of NF-κB and reducing the levels of COX-2 and PGF2αin uterine tissues.展开更多
文摘A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated into the closed-loop system model, which includes: a model based upon the mean force-velocity (f-v) behaviour; and a model synthesis comprising inherent nonsmooth hysteretic force and the force limiting properties of the MR damper. The vehicle models are analyzed to study the vibration attenuation performance of the MR-damper using the semi-active force tracking PI control algorithm. The simulation results are also presented to demonstrate the influence of the damper nonlinearity, specifically the hysteresis, on the suspension performance. The results show that the proposed control strategy can yield superior vibration attenuation performance of the vehicle suspension actuated by the controllable MR-damper not only in the sprung mass resonance and the ride zones, but also in the vicinity of the wheel-hop. The results further show that the presence of damper hystersis deteriorates the suspension performance.
基金Project(2011GZ0131) supported by the Sichuan Province Key Technology Support Program,China
文摘Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.
基金Project(1114022-15) supported by the Major Science and Technology Research Projects of Guangxi Province,China
文摘The layered LiNi0.6Co0.2Mn0.2-yMgyO2-zFz（0≤y≤0.12, 0≤z≤0.08） cathode materials were synthesized by combining co-precipitation method and high temperature solid-state reaction, with the help of the ball milling, to investigate the effects of F-Mg doping on LiNi0.6Co0.2Mn0.2O）2. Compared with previous studies, this doping treatment provides substantially improved electrochemical performance in terms of initial coulombic efficiency and cycle performance. The LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 electrode delivers an high capacity retention of 98.6% during the first cycle and a discharge capacity of 189.7 m A·h/g（2.8-4.4 V at 0.2 C）, with the capacity retention of 96.3% after 100 cycles. And electrochemical impedance spectroscopy（EIS） results show that Mg-F co-doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance. It is demonstrated that LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 is a promising cathode material for lithium-ion batteries for excellent electrochemical properties.
文摘Objective:To observe the effects of electroacupuncture(EA)on uterine prostaglandin F2α(PGF2α),cyclooxygenase 2(COX-2)and nuclear factorκB(NF-κB)in rats with primary dysmenorrhea(PD)and to discuss the possible mechanism in EA intervening PD.Methods:Forty Sprague-Dawley female rats were randomly divided into a blank group,a model group,an EA group and an ibuprofen group,with 10 rats in each group.The PD model was established using estradiol benzoate combined with oxytocin in the model group,EA group and ibuprofen group.At the same time of modeling,rats in the EA group were given EA at Guanyuan(CV 4)and Sanyinjiao(SP 6)once a day for 20 min each time for 10 consecutive days.Ibuprofen was intragastrically administered once a day for 10 consecutive days in the ibuprofen group.The same amount of normal saline was intragastrically administered once a day for 10 consecutive days in the blank group and model group.The number of writhing of rats in each group within 30 min was compared on the 11th day just after the interventions.The uterine homogenate supernatant was separated and the PGF2αlevel was detected by enzyme-linked immunosorbent assay.Western blot was applied for the detection of the expression levels of COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues.Results:Compared with the blank group,the number of writhing in the model group increased significantly(P<0.01),and the expression levels of PGF2α,COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues were significantly increased(all P<0.01).Compared with the model group,the number of writhing in the EA group and ibuprofen group were significantly reduced(both P<0.01),and the expression levels of PGF2αand COX-2 protein in uterine tissues were significantly reduced(both P<0.01).Compared with the model group,the phospho-NF-κB p65 level in uterine tissues in the EA group was significantly reduced(P<0.01).Compared with the ibuprofen group,the phospho-NF-κB p65 level in the EA group was significantly reduced(P<0.01).Conclusion:The mechanism of EA for PD rats may be related to inhibiting the phosphorylation of NF-κB and reducing the levels of COX-2 and PGF2αin uterine tissues.
