This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coi...This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coil of the electromagnet is electrified with proper control strategy, the electromagnet can exert magnetic force opposite to the direction of structural deformation so that the structural vibration is attenuated. A mathematical model is developed based on the equivalent current method to calculate the electromagnetic control force produced by EMCLD. The governing equations of the system are obtained using Hamilton＇s Principle and then reduced with the assumed-mode method. A simulation on vibration control of a cantilever beam is conducted under the velocity proportional feedback to demonstrate the energy dissipation capability of EMCLD, and the beam system with the same parameter is experimented. The results of experiment and simulation are compared and the results show that the EMCLD is an effective means for suppressing modal vibration. The results also indicate that the beam system has better control performance for larger control current. The EMCLD method presented in this paper provides an applicable and efficient tool for the vibration control of structures.展开更多
A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characteriz...A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^(1/2)@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.展开更多
The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of d...The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of double sorts of variables, and the Hamilton canonical equations are established. The 3-dimensional problem of magneto-electro-elastic structure which is investigated in Euclidean space commonly is converted into symplectic system. At the same time the Lagrange system is converted into Hamiltonian system. As an example, the dynamic characteristics of the simply supported functionally graded magneto-electro-elastic material （FGMM） plate and pipe are investigated. Finally, the problem is solved by symplectic algorithm. The results show that the physical quantities of displacement, electric potential and magnetic potential etc. change continuously at the interfaces between layers under the transverse pressure while some other physical quantities such as the stress, electric and magnetic displacement are not continuous. The dynamic stiffness is increased by the piezoelectric effect while decreased by the piezomagnetic effect.展开更多
A simple and rapid method to prepare efficient electro-competent cells of Xanthomonas campestris pv. campestris was generated, with up to 100-fold transformation efficiencies over the existing procedures. The overnigh...A simple and rapid method to prepare efficient electro-competent cells of Xanthomonas campestris pv. campestris was generated, with up to 100-fold transformation efficiencies over the existing procedures. The overnight cultures were treated with sucrose solution and micro-centrifuged at room temperature;the entire electro-competent cells generation process can be completed in 15 minutes. It overcomes the complication and time-consuming shortcomings of the traditional conjugation or electro-transformation methods in this strain. Both the replicative plasmids and non-replicative plasmids could be transformed or integrated efficiently using this method. And the DNA concentration, cells growth stage, field strength and recovery time all had influences on the transformation efficiency. In the optimal conditions, the transformation efficiency for the replicative plasmids was 10<sup>9</sup> transformants per microgram DNA, and for non-replicative plasmids was 150 transformants per microgram DNA. Further with the homology sequences, two chromosomal target genes were deleted efficiently and the knockout strains were obtained easily.展开更多
This work will create an electro-dialysis cell model that has the purpose of refining anodic scrap copper—an element that currently must be returned to the copper conversion process. The cell modeling is based on Ohm...This work will create an electro-dialysis cell model that has the purpose of refining anodic scrap copper—an element that currently must be returned to the copper conversion process. The cell modeling is based on Ohm’s Law, while the resulting copper deposit morphology is studied through the thickness of the layer deposited on the surface and the electric current lines traced from the anode to the cathode. The use of the model demonstrated that it is possible to effectively predict the specific energy consumption required for the refinement of the anodic scrap copper, and the morphology of the cathode obtained, with a margin of error of 9%.展开更多
INTRODUCTIONIt has been reported in many studies that electro-acupuncture(EA)can positively regulate erythrocyticimmunity and T-lymphocytic subgroups.Nevertheless,its mechanism remains to be explored.In thepresent stu...INTRODUCTIONIt has been reported in many studies that electro-acupuncture(EA)can positively regulate erythrocyticimmunity and T-lymphocytic subgroups.Nevertheless,its mechanism remains to be explored.In thepresent study,a multi-group,multi-stepped and multi-indexed observation was conducted on the effects of EA展开更多
The electro-hydraulic servo system was studied to cancel the amplitude attenuation and phase delay of its sinusoidal response,by developing a network using normalized least-mean-square (LMS) adaptive filtering algorit...The electro-hydraulic servo system was studied to cancel the amplitude attenuation and phase delay of its sinusoidal response,by developing a network using normalized least-mean-square (LMS) adaptive filtering algorithm.The command input was corrected by weights to generate the desired input for the algorithm,and the feedback was brought into the feedback correction,whose output was the weighted feedback.The weights of the normalized LMS adaptive filtering algorithm were updated on-line according to the estimation error between the desired input and the weighted feedback.Thus,the updated weights were copied to the input correction.The estimation error was forced to zero by the normalized LMS adaptive filtering algorithm such that the weighted feedback was equal to the desired input,making the feedback track the command.The above concept was used as a basis for the development of amplitude phase control.The method has good real-time performance without estimating the system model.The simulation and experiment results show that the proposed amplitude phase control can efficiently cancel the amplitude attenuation and phase delay with high precision.展开更多
AIM To observe whether there are differences in the effects of electro-acupuncture(EA) and moxibustion(Mox) in rats with visceral hypersensitivity. METHODS EA at 1 m A and 3 m A and Mox at 43?℃ and 46?℃ were applied...AIM To observe whether there are differences in the effects of electro-acupuncture(EA) and moxibustion(Mox) in rats with visceral hypersensitivity. METHODS EA at 1 m A and 3 m A and Mox at 43?℃ and 46?℃ were applied to the Shangjuxu(ST37, bilateral) acupoints in model rats with visceral hypersensitivity. Responses of wide dynamic range neurons in dorsal horns of the spinal cord were observed through the extracellular recordings. Mast cells(MC) activity in the colons of rats were assessed, and 5-hydroxytryptamine(5-HT), 5-hydroxytryptamine 3 receptor(5-HT3R) and 5-HT4Rexpressions in the colons were measured.RESULTS Compared with normal control group, responses of wide dynamic range neurons in the dorsal horn of the spinal cord were increased in the EA at 1 m A and 3 m A groups(1 m A: 0.84 ± 0.74 vs 2.73 ± 0.65, P < 0.001; 3 m A: 1.91 ± 1.48 vs 6.44 ± 1.26, P < 0.001) and Mox at 43?℃ and 46?℃ groups(43?℃: 1.76 ± 0.81 vs 4.14 ± 1.83, P = 0.001; 46?℃: 5.19 ± 2.03 vs 7.91 ± 2.27, P = 0.01). MC degranulation rates and the expression of 5-HT, 5-HT3 R and 5-HT4 R in the colon of Mox 46?℃ group were decreased compared with model group(MC degranulation rates: 0.47 ± 0.56 vs 0.28 ± 0.78, P < 0.001; 5-HT: 1.42 ± 0.65 vs 7.38 ± 1.12, P < 0.001; 5-HT3R: 6.62 ± 0.77 vs 2.86 ± 0.88, P < 0.001; 5-HT4R: 4.62 ± 0.65 vs 2.22 ± 0.97, P < 0.001). CONCLUSION The analgesic effects of Mox at 46?℃ are greater than those of Mox at 43?℃, EA 1 m A and EA 3 m A.展开更多
This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentratio...This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation eff...展开更多
A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens...A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol· L^-1 Ce（NO3 ）3 The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol · L^-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy （EIS） measurements. The surface morphology of the coating was studied using scanning electron microscopy （SEM）. The composition and chemical percent of the coating were examined by X-ray dispersion energy （EDAX）. The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.展开更多
A proportional integral derivative （PID） controller is designed and attached to electro-hydraulic servo actuator system （EHSAS） to control the angular position of the rotary actuator which control the movable surf...A proportional integral derivative （PID） controller is designed and attached to electro-hydraulic servo actuator system （EHSAS） to control the angular position of the rotary actuator which control the movable surface of space vehicles. The PID gain parameters are optimized by the genetic algorithm （GA）. The controller is verified on the new state-space model of servo-valves attached to the physical rotary actuator by SIMULINK program. The controller and the state-space model are verified experimentally. Simulation and experimental results verify the effectiveness of the PID controller adaptive by GA to control the angular position of the rotary actuator as compared with the classical PID controller and the compensator controller.展开更多
The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in a...The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in aircraft EHA systems. In order to reduce churning losses at high speeds, more attention should be given to the design of an insert. In this paper, the effect of an insert with different design parameters on churning losses is investigated through Computational Fluid Dynamics(CFD) simulation and experiments by calculating the difference between churning losses torques of the test pump with and without the insert based on a high-speed churning losses test rig.Analytical results show that the gap between the insert and the cylinder is critical for churning losses reduction. It is found that the churning losses of the test pump can be reduced with a decreasing gap between the cylinder block and the insert at high speeds. This is because the insert can decrease the turbulence occurrence at high speeds. The results can be used for flow field analysis and optimization of the high-speed EHA pump and provide a new method for improving efficiency of high-speed EHA pumps.展开更多
Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within th...Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.展开更多
Objective： Acupuncture has a definite therapeutic effect on chronic obstructive pulmonary disease （COPD）, and the cholinergic anti-inflammatory pathway （CAP） has been shown to be involved in regula- tion of infla...Objective： Acupuncture has a definite therapeutic effect on chronic obstructive pulmonary disease （COPD）, and the cholinergic anti-inflammatory pathway （CAP） has been shown to be involved in regula- tion of inflammation. In this study, we investigated whether electro-acupuncture （EA） affects the CAP in COPD,Methods： Sprague-Dawley rats were induced into COPD through exposure to cigarette smoke combined with lipopolysaccharide. EA treatment was applied at Zusanli （ST36） and Feishu （BL13） points for 30 min/d for 7 d. Seventy-two rats were randomly divided into six study groups, including normal, normal ＋ EA, normal ＋ α-bungarotoxin （α-BGT） （the antagonist of the nicotinic acetylcholine receptor α7 subunit （α7nAChR）） ＋ EA, COPD, COPD ＋ EA, and COPD ＋ α-BGT ＋ EA. Lung function, pathology and vagus nerve discharge were tested. The levels of acetylcholine （ACh）, acetylcholinesterase （ACHE）, interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-ct） in bronchoalveolar lavage fluid （BALF） and lung tissue were measured by enzyme-linked immunosorbent assay. The mRNA and protein expression and immunoreac- tivity of α7nAChR and its postreceptor inflammation signal pathway, including janus kinase 2 （JAK2）, sig- nal transducers and activators of transcription 3 （STAT3）, nuclear factor-KB （NF-KB）, were observed by quantitative reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry. Results： Compared with normal rats, there were a significant decline in lung function and discharge of the vagus nerve （P 〈 0.01）, a marked sign of lung inflammation and an increase of ACh, ACHE, IL-6 and TNF-α level in BALF or lung tissue （P 〈 0.05, P 〈 0.01 ） and higher expression of 0t7nAChR, JAK2, STAT3 and NF-αB （P 〈 0.05, P 〈 0.01） in the COPD rats. In rats receiving EA, the lung function and vagal discharge were enhanced （P 〈 0.01 ）, lung inflammation was improved and the levels of ACh, ACHE, IL-6 and TNF-α were decreased （P 〈 0.01）. Further, the expression of α7nAChR, JAK2, STAT3 and NF-κB was downregulated （P 〈 0.05, P 〈 0.01 ）. However, the above effects of EA were blocked in rats injected with α-BCT （P 〈 0.01 ）. Conclusion： EA treatment can reduce the lung inflammatory response and improve lung function in COPD, which may be related to its involvement in the regulation of CAP.展开更多
Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear paramete...Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear parameters, viz. the flow gain coefficient of servo valve and total factors of flow-pressure coefficient. Taking trace error of torque control system to zero as control object, this article designs the adaptive nonlinear optimal compensation control strategy, which regards torque control output of closed-loop controller converging to zero as the control target, to optimize torque tracking performance. Electro-hydraulic load simulator is a typical case of the torque system which is strongly coupled with a hydraulic positioning system. This article firstly builds and analyzes the mathematical models of hydraulic torque and positioning system, then designs an adaptive nonlinear optimal compensation controller, proves the validity of parameters estimation, and shows the comparison data among three control structures with various typical operating conditions, including proportion-integral-derivative (PID) controller only, the velocity synchronizing controller plus P1D controller and the proposed adaptive nonlinear optimal compensation controller plus PID controller. Experimental results show that systems' nonlinear parameters are estimated exactly using the proposed method, and the trace accuracy of the torque system is greatly enhanced by adaptive nonlinear optimal compensation control, and the torque servo system capability against sudden disturbance can be greatly improved.展开更多
The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However...The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However,the nonlinearity of its double-input single-output system poses a great challenge for system control.This study proposes a novel EHA with adaptive pump displacement and variable motor speed(EHA-APVM).A closed-loop position is realized using a servomotor.Moreover,the displacement varies with the system pressure;thus,the EHA-APVM is a single-input and single-output system.Firstly,the working principles of the EHA-APVM and the pump used in the system are introduced.Secondly,a nonlinear mathematical model of the proposed EHA-APVM control system is established,and a feedback back-stepping(FBBS)control algorithm is introduced to transform the complex nonlinear system into a linear system on the basis of the back-stepping control theory.Finally,simulation results prove that the EHA-APVM has a quick response and high robustness to variations of the load and the pump displacement.In this work,the size and weight of the motor are significantly reduced because the maximum power requirement is reduced,which is very beneficial for using the actuator in airborne equipment.展开更多
In this paper, the free vibration of magneto- electro-elastic （MEE） nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rect...In this paper, the free vibration of magneto- electro-elastic （MEE） nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rectan gular plate subjected to the biaxial force, external electric potential, external magnetic potential, and temperature rise. By using the Hamilton＇s principle, the governing equations and boundary conditions are derived and then solved analytically to obtain the natural frequencies of MEE nanoplates. A parametric study is presented to examine the effect of the nonlocal parameter, thermo-magneto-electro-mechanical loadings and aspect ratio on the vibration characteristics of MEE nanoplates. It is found that the natural frequency is quite sensitive to the mechanical loading, electric loading and magnetic loading, while it is insensitive to the thermal loading.展开更多
This study examined the effect of electro-acupuncture (EA) combined with transcranial magnetic stimulation (TMS) therapy at different time windows on learning and memory ability of rats with cerebral infarction and th...This study examined the effect of electro-acupuncture (EA) combined with transcranial magnetic stimulation (TMS) therapy at different time windows on learning and memory ability of rats with cerebral infarction and the underlying mechanism.Two hundred SD rats were randomly divided into four groups:normal group,sham-operated group,model group and EA+TMS group,and each group was then divided into five sub-groups in terms of the different time to start treatment post operation:6,12,24,48 and 72 h.Cerebral infarction models were established in the model and the EA+TMS groups by left middle cerebral artery occlusion/reperfusion (MCAO/R).After treatment for 14 d,the Morris water maze test was applied to examine the spatial learning and memory abilities of rats.In infarcted area,the expression of caspase-3 was immunohistochemically detected,and real-time fluorescent quantitative PCR was used to measure the expression of Bcl-2 mRNA.The results showed that in EA+TMS group compared with model group at the same treatment time windows,the escape latency was substantially shortened,the expression of caspase-3 was considerably decreased and the expression level of Bcl-2 mRNA significantly increased (P<0.05).In the EA+TMS sub-groups,the escape latency was shortest,the expression level of caspase-3 lowest,and the expression level of Bcl-2 mRNA highest at the treatment time window of 24 h.It was concluded that EA combined with TMS can promote neurological function of rats with cerebral infarction by increasing the expression level of Bcl-2 mRNA and decreasing the expression of caspase-3.The best time window is 24 h after perfusion treatment to ischemia.展开更多
基金National Natural Science Foundation of China (50275114)
文摘This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coil of the electromagnet is electrified with proper control strategy, the electromagnet can exert magnetic force opposite to the direction of structural deformation so that the structural vibration is attenuated. A mathematical model is developed based on the equivalent current method to calculate the electromagnetic control force produced by EMCLD. The governing equations of the system are obtained using Hamilton＇s Principle and then reduced with the assumed-mode method. A simulation on vibration control of a cantilever beam is conducted under the velocity proportional feedback to demonstrate the energy dissipation capability of EMCLD, and the beam system with the same parameter is experimented. The results of experiment and simulation are compared and the results show that the EMCLD is an effective means for suppressing modal vibration. The results also indicate that the beam system has better control performance for larger control current. The EMCLD method presented in this paper provides an applicable and efficient tool for the vibration control of structures.
基金supported by the National Defense Science and Technology Innovation Zone Project(No.18-H863-05-ZT-001-018-09)
文摘A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^(1/2)@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.
文摘The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of double sorts of variables, and the Hamilton canonical equations are established. The 3-dimensional problem of magneto-electro-elastic structure which is investigated in Euclidean space commonly is converted into symplectic system. At the same time the Lagrange system is converted into Hamiltonian system. As an example, the dynamic characteristics of the simply supported functionally graded magneto-electro-elastic material （FGMM） plate and pipe are investigated. Finally, the problem is solved by symplectic algorithm. The results show that the physical quantities of displacement, electric potential and magnetic potential etc. change continuously at the interfaces between layers under the transverse pressure while some other physical quantities such as the stress, electric and magnetic displacement are not continuous. The dynamic stiffness is increased by the piezoelectric effect while decreased by the piezomagnetic effect.
文摘A simple and rapid method to prepare efficient electro-competent cells of Xanthomonas campestris pv. campestris was generated, with up to 100-fold transformation efficiencies over the existing procedures. The overnight cultures were treated with sucrose solution and micro-centrifuged at room temperature;the entire electro-competent cells generation process can be completed in 15 minutes. It overcomes the complication and time-consuming shortcomings of the traditional conjugation or electro-transformation methods in this strain. Both the replicative plasmids and non-replicative plasmids could be transformed or integrated efficiently using this method. And the DNA concentration, cells growth stage, field strength and recovery time all had influences on the transformation efficiency. In the optimal conditions, the transformation efficiency for the replicative plasmids was 10<sup>9</sup> transformants per microgram DNA, and for non-replicative plasmids was 150 transformants per microgram DNA. Further with the homology sequences, two chromosomal target genes were deleted efficiently and the knockout strains were obtained easily.
文摘This work will create an electro-dialysis cell model that has the purpose of refining anodic scrap copper—an element that currently must be returned to the copper conversion process. The cell modeling is based on Ohm’s Law, while the resulting copper deposit morphology is studied through the thickness of the layer deposited on the surface and the electric current lines traced from the anode to the cathode. The use of the model demonstrated that it is possible to effectively predict the specific energy consumption required for the refinement of the anodic scrap copper, and the morphology of the cathode obtained, with a margin of error of 9%.
基金the National Natural Science Foundation of China,№39970888.
文摘INTRODUCTIONIt has been reported in many studies that electro-acupuncture(EA)can positively regulate erythrocyticimmunity and T-lymphocytic subgroups.Nevertheless,its mechanism remains to be explored.In thepresent study,a multi-group,multi-stepped and multi-indexed observation was conducted on the effects of EA
基金Project(50905037) supported by the National Natural Science Foundation of ChinaProject(20092304120014) supported by Specialized Research Fund for the Doctoral Program of Higher Education of China+2 种基金 Project(20100471021) supported by the China Postdoctoral Science Foundation Project(LBH-Q09134) supported by Heilongjiang Postdoctoral Science-Research Foundation,China Project (HEUFT09013) supported by the Foundation of Harbin Engineering University,China
文摘The electro-hydraulic servo system was studied to cancel the amplitude attenuation and phase delay of its sinusoidal response,by developing a network using normalized least-mean-square (LMS) adaptive filtering algorithm.The command input was corrected by weights to generate the desired input for the algorithm,and the feedback was brought into the feedback correction,whose output was the weighted feedback.The weights of the normalized LMS adaptive filtering algorithm were updated on-line according to the estimation error between the desired input and the weighted feedback.Thus,the updated weights were copied to the input correction.The estimation error was forced to zero by the normalized LMS adaptive filtering algorithm such that the weighted feedback was equal to the desired input,making the feedback track the command.The above concept was used as a basis for the development of amplitude phase control.The method has good real-time performance without estimating the system model.The simulation and experiment results show that the proposed amplitude phase control can efficiently cancel the amplitude attenuation and phase delay with high precision.
基金Supported by National Basic Research Program of China(973 Program)No.2009CB522900 and No.2015CB554501National Natural Science Foundation of China,No.30973784
文摘AIM To observe whether there are differences in the effects of electro-acupuncture(EA) and moxibustion(Mox) in rats with visceral hypersensitivity. METHODS EA at 1 m A and 3 m A and Mox at 43?℃ and 46?℃ were applied to the Shangjuxu(ST37, bilateral) acupoints in model rats with visceral hypersensitivity. Responses of wide dynamic range neurons in dorsal horns of the spinal cord were observed through the extracellular recordings. Mast cells(MC) activity in the colons of rats were assessed, and 5-hydroxytryptamine(5-HT), 5-hydroxytryptamine 3 receptor(5-HT3R) and 5-HT4Rexpressions in the colons were measured.RESULTS Compared with normal control group, responses of wide dynamic range neurons in the dorsal horn of the spinal cord were increased in the EA at 1 m A and 3 m A groups(1 m A: 0.84 ± 0.74 vs 2.73 ± 0.65, P < 0.001; 3 m A: 1.91 ± 1.48 vs 6.44 ± 1.26, P < 0.001) and Mox at 43?℃ and 46?℃ groups(43?℃: 1.76 ± 0.81 vs 4.14 ± 1.83, P = 0.001; 46?℃: 5.19 ± 2.03 vs 7.91 ± 2.27, P = 0.01). MC degranulation rates and the expression of 5-HT, 5-HT3 R and 5-HT4 R in the colon of Mox 46?℃ group were decreased compared with model group(MC degranulation rates: 0.47 ± 0.56 vs 0.28 ± 0.78, P < 0.001; 5-HT: 1.42 ± 0.65 vs 7.38 ± 1.12, P < 0.001; 5-HT3R: 6.62 ± 0.77 vs 2.86 ± 0.88, P < 0.001; 5-HT4R: 4.62 ± 0.65 vs 2.22 ± 0.97, P < 0.001). CONCLUSION The analgesic effects of Mox at 46?℃ are greater than those of Mox at 43?℃, EA 1 m A and EA 3 m A.
基金the Science and Technology Department of Zhejiang Province (No.2006C13120).
文摘This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation eff...
基金Project supported by the Office of the New Material and Clean Chemistry Research of the Tabriz University
文摘A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol· L^-1 Ce（NO3 ）3 The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol · L^-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy （EIS） measurements. The surface morphology of the coating was studied using scanning electron microscopy （SEM）. The composition and chemical percent of the coating were examined by X-ray dispersion energy （EDAX）. The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.
文摘A proportional integral derivative （PID） controller is designed and attached to electro-hydraulic servo actuator system （EHSAS） to control the angular position of the rotary actuator which control the movable surface of space vehicles. The PID gain parameters are optimized by the genetic algorithm （GA）. The controller is verified on the new state-space model of servo-valves attached to the physical rotary actuator by SIMULINK program. The controller and the state-space model are verified experimentally. Simulation and experimental results verify the effectiveness of the PID controller adaptive by GA to control the angular position of the rotary actuator as compared with the classical PID controller and the compensator controller.
基金financial supports from the National Basic Research Program of China(973 Program)(No.2014CB046403)the National Natural Science Foundation of China(No.1737110)
文摘The speed of an Electro-Hydrostatic Actuator(EHA) pump can recently reach 20000 r/min, and its churning losses increase obviously with an increasing speed, which results in low efficiency and thus increasing heat in aircraft EHA systems. In order to reduce churning losses at high speeds, more attention should be given to the design of an insert. In this paper, the effect of an insert with different design parameters on churning losses is investigated through Computational Fluid Dynamics(CFD) simulation and experiments by calculating the difference between churning losses torques of the test pump with and without the insert based on a high-speed churning losses test rig.Analytical results show that the gap between the insert and the cylinder is critical for churning losses reduction. It is found that the churning losses of the test pump can be reduced with a decreasing gap between the cylinder block and the insert at high speeds. This is because the insert can decrease the turbulence occurrence at high speeds. The results can be used for flow field analysis and optimization of the high-speed EHA pump and provide a new method for improving efficiency of high-speed EHA pumps.
基金funding support from the National Natural Science Foundation of China (51722404 and 51674177)
文摘Due to the serious greenhouse gas effects caused by the increasing concentration of atmospheric CO_2,carbon capture and storage(CCS) has been an important area of research and many technologies are developed within this field. Molten salt CO_2 capture and electrochemical transformation(MSCC-ET) process is a desirable method due to a high CO_2 solubility, a wide potential window of molten salts and easily-controlled electrode reactions. Generally, electro-splitting CO_2 in molten salts begins with CO_2 absorption reactions to form CO_3^(2-), which is then followed by the carbon deposition at the cathode and O_2 evolution at the anode. As a result, CO_2 is electro-converted to O_2 and carbon with different morphologies, compositions, microstructures and functional properties. This report introduces the MSCC-ET process, summarizes the reactions occurring in the molten salts and at the electrode surfaces, as well as the morphological variations of the cathodic products. The inert anode materials, cost estimation and scale-up evaluation of the process are then discussed. It is presumed that with a comprehensive understanding of the electrode reactions during electrolysis and the functional properties of carbon materials obtained during CO_2 electro-splitting can provide a foundation for further developing this environmentally friendly process.
基金supported by grants from the National Natural Science Foundation of China(No. 81373743)Outstanding Young Talents Support Program of Anhui(No. 20140181)
文摘Objective： Acupuncture has a definite therapeutic effect on chronic obstructive pulmonary disease （COPD）, and the cholinergic anti-inflammatory pathway （CAP） has been shown to be involved in regula- tion of inflammation. In this study, we investigated whether electro-acupuncture （EA） affects the CAP in COPD,Methods： Sprague-Dawley rats were induced into COPD through exposure to cigarette smoke combined with lipopolysaccharide. EA treatment was applied at Zusanli （ST36） and Feishu （BL13） points for 30 min/d for 7 d. Seventy-two rats were randomly divided into six study groups, including normal, normal ＋ EA, normal ＋ α-bungarotoxin （α-BGT） （the antagonist of the nicotinic acetylcholine receptor α7 subunit （α7nAChR）） ＋ EA, COPD, COPD ＋ EA, and COPD ＋ α-BGT ＋ EA. Lung function, pathology and vagus nerve discharge were tested. The levels of acetylcholine （ACh）, acetylcholinesterase （ACHE）, interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-ct） in bronchoalveolar lavage fluid （BALF） and lung tissue were measured by enzyme-linked immunosorbent assay. The mRNA and protein expression and immunoreac- tivity of α7nAChR and its postreceptor inflammation signal pathway, including janus kinase 2 （JAK2）, sig- nal transducers and activators of transcription 3 （STAT3）, nuclear factor-KB （NF-KB）, were observed by quantitative reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry. Results： Compared with normal rats, there were a significant decline in lung function and discharge of the vagus nerve （P 〈 0.01）, a marked sign of lung inflammation and an increase of ACh, ACHE, IL-6 and TNF-α level in BALF or lung tissue （P 〈 0.05, P 〈 0.01 ） and higher expression of 0t7nAChR, JAK2, STAT3 and NF-αB （P 〈 0.05, P 〈 0.01） in the COPD rats. In rats receiving EA, the lung function and vagal discharge were enhanced （P 〈 0.01 ）, lung inflammation was improved and the levels of ACh, ACHE, IL-6 and TNF-α were decreased （P 〈 0.01）. Further, the expression of α7nAChR, JAK2, STAT3 and NF-κB was downregulated （P 〈 0.05, P 〈 0.01 ）. However, the above effects of EA were blocked in rats injected with α-BCT （P 〈 0.01 ）. Conclusion： EA treatment can reduce the lung inflammatory response and improve lung function in COPD, which may be related to its involvement in the regulation of CAP.
基金National Natural Science Foundation of China (50825502)
文摘Directing to the strong position coupling problem of electro-hydraulic load simulator (EHLS), this article presents an adaptive nonlinear optimal compensation control strategy based on two estimated nonlinear parameters, viz. the flow gain coefficient of servo valve and total factors of flow-pressure coefficient. Taking trace error of torque control system to zero as control object, this article designs the adaptive nonlinear optimal compensation control strategy, which regards torque control output of closed-loop controller converging to zero as the control target, to optimize torque tracking performance. Electro-hydraulic load simulator is a typical case of the torque system which is strongly coupled with a hydraulic positioning system. This article firstly builds and analyzes the mathematical models of hydraulic torque and positioning system, then designs an adaptive nonlinear optimal compensation controller, proves the validity of parameters estimation, and shows the comparison data among three control structures with various typical operating conditions, including proportion-integral-derivative (PID) controller only, the velocity synchronizing controller plus P1D controller and the proposed adaptive nonlinear optimal compensation controller plus PID controller. Experimental results show that systems' nonlinear parameters are estimated exactly using the proposed method, and the trace accuracy of the torque system is greatly enhanced by adaptive nonlinear optimal compensation control, and the torque servo system capability against sudden disturbance can be greatly improved.
基金financially supported by the National Natural Science Foundation of China(No’s.51375029 and 51775013).
文摘The variable pump displacement and variable motor speed electro-hydrostatic actuator(EHA),one of the three types of EHAs,has advantages such as short response time,flexible speed regulation,and high efficiency.However,the nonlinearity of its double-input single-output system poses a great challenge for system control.This study proposes a novel EHA with adaptive pump displacement and variable motor speed(EHA-APVM).A closed-loop position is realized using a servomotor.Moreover,the displacement varies with the system pressure;thus,the EHA-APVM is a single-input and single-output system.Firstly,the working principles of the EHA-APVM and the pump used in the system are introduced.Secondly,a nonlinear mathematical model of the proposed EHA-APVM control system is established,and a feedback back-stepping(FBBS)control algorithm is introduced to transform the complex nonlinear system into a linear system on the basis of the back-stepping control theory.Finally,simulation results prove that the EHA-APVM has a quick response and high robustness to variations of the load and the pump displacement.In this work,the size and weight of the motor are significantly reduced because the maximum power requirement is reduced,which is very beneficial for using the actuator in airborne equipment.
基金supported by the Australian Research Council (DP130104358)Fundamental Research Funds for the Central Universities under Grant number 2013JBM009+1 种基金Program for New Century Excellent Talents in University under Grant number NCET-13-0656Beijing Higher Education Young Elite Teacher Project under Grant number YETP0562
文摘In this paper, the free vibration of magneto- electro-elastic （MEE） nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rectan gular plate subjected to the biaxial force, external electric potential, external magnetic potential, and temperature rise. By using the Hamilton＇s principle, the governing equations and boundary conditions are derived and then solved analytically to obtain the natural frequencies of MEE nanoplates. A parametric study is presented to examine the effect of the nonlocal parameter, thermo-magneto-electro-mechanical loadings and aspect ratio on the vibration characteristics of MEE nanoplates. It is found that the natural frequency is quite sensitive to the mechanical loading, electric loading and magnetic loading, while it is insensitive to the thermal loading.
基金supported by a grant from the National Natural Science Foundation of China (No.30640010)
文摘This study examined the effect of electro-acupuncture (EA) combined with transcranial magnetic stimulation (TMS) therapy at different time windows on learning and memory ability of rats with cerebral infarction and the underlying mechanism.Two hundred SD rats were randomly divided into four groups:normal group,sham-operated group,model group and EA+TMS group,and each group was then divided into five sub-groups in terms of the different time to start treatment post operation:6,12,24,48 and 72 h.Cerebral infarction models were established in the model and the EA+TMS groups by left middle cerebral artery occlusion/reperfusion (MCAO/R).After treatment for 14 d,the Morris water maze test was applied to examine the spatial learning and memory abilities of rats.In infarcted area,the expression of caspase-3 was immunohistochemically detected,and real-time fluorescent quantitative PCR was used to measure the expression of Bcl-2 mRNA.The results showed that in EA+TMS group compared with model group at the same treatment time windows,the escape latency was substantially shortened,the expression of caspase-3 was considerably decreased and the expression level of Bcl-2 mRNA significantly increased (P<0.05).In the EA+TMS sub-groups,the escape latency was shortest,the expression level of caspase-3 lowest,and the expression level of Bcl-2 mRNA highest at the treatment time window of 24 h.It was concluded that EA combined with TMS can promote neurological function of rats with cerebral infarction by increasing the expression level of Bcl-2 mRNA and decreasing the expression of caspase-3.The best time window is 24 h after perfusion treatment to ischemia.
