Speed Identification of Speed Sensorless Linear Induction Motor Based on MRAS

In the linear induction motor control system,the optical grating speed transducer is susceptible to strong magnetic field interference.What's more,it may reduce motor integration and raise device costs.Therefore a speed identification method to replace grating speed transducer is studied in this article.This speed identification method for linear induction motor mainly adopts Model Reference Adaptive Method(Abbreviated as MRAS)and Popov Hyperstability Theory.The research content of this paper can be divided into four parts.First,the mathematical model of the motor based on the model reference adaptive system structure is deduced.Second,the adaptive law of the estimated speed is solved by Popov hyper-stability theory,which ensures the stability of the system.Third,the simulation model of the linear induction motor speed identification control system based on model reference adaptation is built in the MATLAB environment.Finally,the simulation test and analysis are carried out.The simulation results show that the speed identification control system can track the actual speed of the linear induction motor well in the no-load operation and the load operation,and the stability of the system is guaranteed in the full speed range.

Research on Cogging Force Suppression for Toroidal PMLSM Based on Disturbance Observer

For a new type of toroidal permanent magnet linear motor(TPMLSM), this paper analyzes the thrust fluctuation in the constant acceleration operation of the motor from the Angle of the cogging force of the linear motor. For the motor whose structure has been determined and processed, the structural parameters of the motor cannot be changed, and its performance cannot be improved from the perspective of the motor body.Therefore, this paper tries to consider the influence of the cogging force on the normal operation of the motor from the perspective of control. In this paper, starting from the body structure of motor, first on the annular linear motor of the cogging force characteristics were extracted, and its expression is obtained by Fourier decomposition, then investigated considering the cogging force and does not consider the cogging force control of motor model, it can be seen that the control performance deteriorates significantly after considering cogging force of the motor, and the acceleration fluctuation increases significantly during the operation of the motor. On this basis, disturbance observation algorithm is introduced, and feedforward compensation is carried out by extracting the characteristic values of the disturbance model. The results show that the disturbance observer can suppress the thrust fluctuation caused by the motor cogging force to a large extent, and it can reduce the peak-to-peak value of the thrust fluctuation by more than 85% during the motor acceleration operation.

Aged hematopoietic stem cells entrap regulatory T cells to create a prosurvival microenvironment

Although DNA mutation drives stem cell aging,how mutation-accumulated stem cells obtain clonal advantage during aging remains poorly understood.Here,using a mouse model of irradiation-induced premature aging and middle-aged mice,we show that DNA mutation accumulation in hematopoietic stem cells(HSCs)during aging upregulates their surface expression of major histocompatibility complex class II(MHCII).MHCII upregulation increases the chance for recognition by bone marrow(BM)-resident regulatory T cells(Tregs),resulting in their clonal expansion and accumulation in the HSC niche.On the basis of the establishment of connexin 43(Cx43)-mediated gap junctions,BM Tregs transfer cyclic adenosine monophosphate(cAMP)to aged HSCs to diminish apoptotic priming and promote their survival via activation of protein kinase A(PKA)signaling.Importantly,targeting the HSC–Treg interaction or depleting Tregs effectively prevents the premature/physiological aging of HSCs.These findings show that aged HSCs use an active self-protective mechanism by entrapping local Tregs to construct a prosurvival niche and obtain a clonal advantage.

Efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection for the treatment of renal anemia in Chinese hemodialysis patients:A randomized,open-label,parallel-group,noninferiority phase III trial

Background:This study was to explore the clinical efficacy and safety of darbepoetin alfa injection replacing epoetin alfa injection(recombinant human erythropoietin injection,rHuEPO)for the treatment of anemia associated with chronic kidney failure in Chinese patients undergoing hemodialysis.Method:This study was a multicenter,randomized,open-label,intergroup parallel control phase III noninferiority trial from April 19,2013 to September 9,2014 at 25 sites.In this study,the members of the darbepoetin alfa group underwent intravenous administration once per week or once every two weeks.The members of the control drug epoetin alfa group underwent intravenous administration two or three times per week.All subjects underwent epoetin alfa administration during the 8-week baseline period.After that,subjects were randomly assigned to the darbepoetin alfa group or epoetin alfa group.The noninferiority in the changes of the average Hb concentrations from the baseline to the end of the evaluation period(noninferiority threshold:-1.0 g/dl)was tested between the two treatments.The time-dependent hemoglobin(Hb)concentration and the maintenance rate of the target Hb concentration(the proportion of subjects with Hb concentrations between 10.0 and 12.0 g/dl)were also evaluated.Iron metabolism,including changes in the serum iron,total iron-binding capacity,ferritin,transferrin saturation,and comparisons of the dose adjustments between the two groups during the treatment period were analyzed further.Adverse events(AEs)were also observed and compared,and the safety was analyzed between the two treatment groups.The conversion rate switching from epoetin alfa to darbepoetin alfa was also discussed.SAS?software version 9.2 was used to perform all statistical analyses.Descriptive statistics were used for all efficacy,safety,and demographic variable analyses,including for the primary efficacy indicators.Results:Four hundred and sixty-six patients were enrolled in this study,and ultimately 384 cases were analyzed for safety,including 267 cases in the darbepoetin alfa group and 117 cases in the epoetin alfa group.There were 211 cases in the per-protocol set,including 152 cases in the darbepoetin alfa group and 59 cases in the epoetin alfa group.The changes in the average Hb concentrations from the baseline to the end of the evaluation period were-0.07 and-0.15 g/dl in the darbepoetin alfa group and epoetin alfa group respectively.The difference between the two groups was 0.08 g/dl(95%confidence interval[CI]:-0.22 to 0.39),and the lower limit of the 95%CI was-0.22>-1.0 g/dl.The average Hb concentrations of the two groups were 10.88-11.43 g/dl(darbepoetin alfa)and 10.91-11.38 g/dl(epoetin alfa)during the study period of Weeks 0-28,with the maintenance rates of the target Hb concentration ranging within 71%-87%and 78%-95%in the darbepoetin alfa group and epoetin alfa group respectively.During the period of comparison between the two groups,the incidence of AEs in the darbepoetin alfa group was 61.42%,while in the epoetin alfa group it was 56.41%.All of the adverse events and reactions in the study were those commonly associated with hemodialysis.Conclusion:The overall efficacy and safety of darbepoetin alfa for the treatment of Chinese renal anemia patients undergoing hemodialysis are consistent with those of epoetin alfa.

Darbepoetin alfa injection versus epoetin alfa injection for treating anemia of Chinese hemodialysis patients with chronic kidney failure:A randomized,open-label,parallel-group,non-inferiority Phase III trail

Background:Erythropoietin is a glycoprotein that mainly regulates erythropoiesis.In patients with chronic renal failure with anemia,darbepoetin alfa can stimulate erythropoiesis,correct anemia,and maintain hemoglobin levels.This study was designed to demonstrate the efficacy and safety of darbepoetin alfa injections as being not inferior to epoetin alfa injections(Recombinant Human Erythropoietin injection,rHuEPO)when maintaining hemoglobin(Hb)levels within the target range(10.0-12.0 g/dL)for the treatment of renal anemia.Methods:Ninety-five patients were enrolled in this study from April 15,2013 to April 10,2014 at 25 sites.In this study,patients(n=95)aged 18-70 years were randomized into a once per week intravenous darbepoetin alfa group(n=56)and a twice or three times per week intravenous epoetin alfa group(n=39)for 28 weeks,who had anemia with hemoglobin levels between 6 g/dL and 10 g/dL due to chronic kidney disease(CKD)and were undergoing hemodialysis or hemofiltration with ESA-naive(erythropoiesis stimulating agent-naive).The primary efficacy profile was the mean Hb level(the non-inferiority margin was-1.0 g/dL,week 21-28);the secondary efficacy profiles were the Hb increase rate(week 0-4),the target Hb achievement cumulative rate and time,the change trends of the Hb levels,and the target Hb maintenance ratio.Adverse events(AEs)were observed and compared,and the efficacy and safety were analyzed between the two treatment groups.Additionally,the frequencies of dose adjustments between the darbepoetin alfa and epoetin alfa groups were compared during the treatment period.SAS?software version 9.2 was used to perform all statistical analyses.Descriptive statistics were used for all efficacy,safety,and demographic variable analyses,including for the primary efficacy indicators.Results:The mean Hb level was 11.3 g/dL in the darbepoetin alfa group and 10.7 g/dL in the epoetin alfa group,respectively;the difference of the lower limits of the 95%confidence intervals(CI)between the two groups was 0.1 g/dL(>-1.0 g/dL),and non-inferiority was proven;the Hb levels started to increase in the first four weeks at a similar increase rate;no obvious differences were observed between the groups in the target Hb achievement cumulative rates,and the Hb levels as well as the target Hb level maintenance rate changed over time.The incidence of AEs was 62.5%in the darbepoetin alfa group and 76.9%in the epoetin alfa group.All the adverse events observed in the study were those commonly associated with hemodialysis.Conclusion:Darbepoetin alfa intravenously once per week can effectively increase Hb levels and maintain the target Hb levels well,which makes it not inferior to epoetin alfa intravenously twice or three times per week.Darbepoetin alfa shows an efficacy and safety comparable to epoetin alfa for the treatment of renal anemia.