A Loss-model-based Efficiency Optimization Control Method for Induction Traction System of High-speed Train under Emergency Self-propelled Mode

Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.

An extended analysis of cardiovascular benefits of indoor air filtration intervention among elderly:a randomized crossover trial(Beijing indoor air purifier study,BIAPSY)

Objective Evidence on potential cardiovascular benefits of personal-level intervention among the elderly exposed to high levels of particulate matter(PM)remains limited.We aimed to assess improvements in surrogate markers of cardiovascular injury in vulnerable populations at risks by using indoor air filtration units.Methods We conducted a randomized crossover trial for 2 separate 2-week air filtration interventions in 20 households of patients with stable chronic obstructive pulmonary disease and their partners in the winter of 2013,with concurrent measurements of indoor PM.The changes in biomarkers indicative of cardiac injury,atherosclerosis progression and systemic inflammation following intervention were evaluated using linear mixed-effect models.Results In the analysis,average levels of indoor PM with aerodynamic diameters<2.5µm(PM2.5)decreased significantly by 59.2%(from 59.6 to 24.3µg/m3,P<0.001)during the active air filtration.The reduction was accompanied by improvements in levels of high-sensitivity cardiac troponin I by−84.6%(95%confidence interval[CI]:−90.7 to−78.6),growth differentiation factor-15 by−48.1%(95%CI:−31.2 to−25.6),osteoprotegerin by−65.4%(95%CI:−56.5 to−18.7),interleukin-4 by−46.6%(95%CI:−62.3 to−31.0)and myeloperoxidase by−60.3%(95%CI:−83.7 to−3.0),respectively.Conclusion Indoor air filtration intervention may provide potential cardiovascular benefits in vulnerable populations at risks.

Short-term exposure to ambient ozone associated with cardiac arrhythmias in healthy adults

Objective The exact biological mechanism whereby exposure to ambient ozone(O3)may contribute to clinical onset of cardiovascular events remains unclear.In this study,we aim to examine the impacts of O3 exposure on cardiac arrhythmias and potential pathways involved through autonomic dysfunction and myocardial injury.Methods Seventy-three non-smoking healthy adults were followed with 4 repeated measurements of 24-hour ambulatory arrhythmias,heart rate variability,ST-segment deviation,and blood pressure(BP)in Beijing,China,2014‒2016.Generalized additive mixed models coupled with distributed lag nonlinear models were constructed to evaluate the associations and potential interlinks between O3 exposure and outcome measurements.Results During the study period,24-hour average concentrations of ambient O3 were 47.4µg/m3(ranging from 1.0 to 165.9µg/m3).Increased risks of premature ventricular contraction and ventricular tachycardia were associated with interquartile range increases in O3 exposure during the last 5 days before each participant's clinic visit,with relative risks of 2.14(95%confidence interval[CI]:1.95 to 2.32)and 5.47(95%CI:3.51 to 7.43),respectively.Mediation analyses further showed that sympathetic activation,parasympathetic inhibition,and elevated BP levels,as well as heightened risks of ST-segment depression could mediate up to 47.74%of the risks of arrhythmias attributable to O3 exposure.Conclusion Our results suggest that short-term exposure to ambient O3 could prompt the genesis of arrhythmias partially through worsening autonomic function and myocardial burden.

Fuzzy Reliability Function of Linear Combination of Marshall and Olkin’S Bivariate Exponential Distribution

In this paper,the fuzzy reliability function Z=X+Y has been derived.In the case of that X,Y subjects to Marshall-Olkin bivariate exponential distribution,assumingμ=μ1μ2.

Ca&Mn dual-ion hybrid nanostimulator boosting anti-tumor immunity via ferroptosis and innate immunity awakening

Limited by low tumor immunogenicity and the immunosuppressive tumor microenvironment(TME),triple-negative breast cancer(TNBC)has been poorly responsive to immunotherapy so far.Herein,a Ca&Mn dual-ion hybrid nanostimulator(CMS)is constructed to enhance anti-tumor immunity through ferroptosis inducing and innate immunity awakening,which can serve as a ferroptosis inducer and immunoadjuvant for TNBC concurrently.On one hand,glutathione(GSH)depletion and reactive oxygen species(ROS)generation can be achieved due to the mixed valence state of Mn in CMS.On the other hand,as an exotic Ca2+supplier,CMS causes mitochondrial Ca2+overload,which further amplifies the oxidative stress.Significantly,tumor cells undergo ferroptosis because of the inactivation of glutathione peroxidase 4(GPX4)and accumulation of lipid peroxidation(LPO).More impressively,CMS can act as an immunoadjuvant to awaken innate immunity by alleviating intra-tumor hypoxia and Mn2+-induced activation of the STING signaling pathway,which promotes polarization of tumor-associated macrophages(TAMs)and activation of dendritic cells(DCs)for antigen presentation and subsequent infiltration of tumor-specific cytotoxic T lymphocytes(CTLs)into tumor tissues.Taken together,this work demonstrates a novel strategy of simultaneously inducing ferroptosis and awakening innate immunity,offering a new perspective for effective tumor immunotherapy of TNBC.

Dynamic and static performance optimization of dual active bridge DC-DC converters

High efficiency and fast dynamic response are two main control objectives for dual active bridge(DAB)DC-DC converters. Traditional extended phase shift(EPS)control can significantly enhance the conversion efficiency of DAB DC-DC converters by reducing current stress;however, it cannot fulfill fast dynamic response requirements. In this paper, a novel hybrid control scheme consisting of EPS control and direct power control(DPC),named as EPS-DPC, is proposed. EPS-DPC control has salient features in both efficiency and dynamic performance. In order to verify the outstanding performance of the proposed EPS-DPC scheme, an experimental comparison was carried out on a scale-down DAB DC-DC converter among several control strategies, including single phase shift control with traditional voltage-loop(SPS-TVL), EPS control with traditional voltage-loop(EPSVTL), and EPS-DPC. Experimental results have been high consistent with theoretical analysis, and verified these advantages of the proposed EPS-DPC scheme.