Fault Tolerant Control for Networked Control Systems with Packet Loss and Time Delay

In this paper,a fault tolerant control with the consideration of actuator fault for a networked control system （NCS） with packet loss is addressed.The NCS with data packet loss can be described as a switched system model.Packet loss dependent Lyapunov function is used and a fault tolerant controller is proposed respectively for arbitrary packet loss process and Markovian packet loss process.Considering a controlled plant with external energy-bounded disturbance,a robust H ∞ fault tolerant controller is designed for the NCS.These results are also expanded to the NCS with packet loss and networked-induced delay.Numerical examples are given to illustrate the effectiveness of the proposed design method.

Longitudinal corner crack of chamfered slab and optimization of mould

Chamfered mould has gradually become a new technology equipment to eliminate transverse corner crack.However,longitudinal corner crack ratio of chamfered slab was very high.Solidification microstructure was detected in the area where the longitudinal corner crack occurred.Effect of narrow face shape and taper distribution of mould copper plate on longitudinal corner crack was studied by industrial tests.Water velocity distribution in the narrow copper plate was studied by numerical simulation.On the premise of preventing cooling water from nuclear boiling,improvement measures of mould cooling process and water seam structure were put forward through heat transfer calculation.The results showed that local taper of the meniscus region of mould should be increased to prevent generation of longitudinal corner crack.Chamfering slope length of narrow copper plate should be controlled within 55 mm,and chamfering angle should be controlled at about 30°.Average water velocity should be more than 7.0 m/s.The flat and chamfering regions of narrow copper plate working face should be designed as double taper and funnel structure,respectively.The water seam in the chamfering region should preferentially choose the combined cooling structure with two holes and one slot.In order to prevent the extension of longitudinal corner crack,chamfered narrow face foot roller should be used.

Microstructural Characterization of Welded Joint in Duplex Stainless Steel by Laser Continuous Heat Treatment

Microstructural characterization in fusion zone of the laser continuous heat treatment welded joint was in vestigated. The results showed that the martensite-like microstructure is the face centered cubic （FCC） crystal structure so that it can be identified as the secondary austenite. The dislocation is observed inside and outside the seconda ry austenite, whereas inclusion is not found in the vicinity of the secondary austenite. In the fusion zone, there is a kind of carbide precipitate which is identified as M23 C6 by the means of transmission electron microscope （TEM）. The carbide precipitate is a representative mode of transformation, which can be generated by the eutectoid reaction. Furthermore, the formation mechanisms of the secondary austenite and chromium carbide are analyzed.

Evaluation of Safety and Efficacy of Qinming8631 DR Implantable Cardiac Pacemaker in Chinese Patients： A Prospective, Multicenter, Randomized Controlled Trial of the First Domestically Developed Pacemaker of China

Background：High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia,and a domestically developed pacemaker will help lower the burden.This study aimed to evaluate the safety and efficacy ofQinming8631 DR （Qinming Medical,Baoji,China）,the first domestically developed dual-chamber pacemaker of China,compared with a commercially available pacemaker Talos DR （Biotronik,Berlin,Germany） in Chinese patients.Methods：A prospective randomized trial was conducted at 14 centers in China.Participants were randomized into trial （Qinming8631 DR） and control （Talos DR） groups.Parameters of the pacing systems were collected immediately after device implantation and during follow-ups.The effective pacing rate at 6-month follow-up was recorded as the primary end point.Electrical properties,magnet response,single-and double-pole polarity conversion,rate response function,and adverse events of the pacing system were analyzed.The Cochran-Mantel-Haenszel Chi-square test,paired t-test,and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data.Results：A total of 225 patients with a diagnosis ofbradyarrhythmia and eligible for this study were randomly enrolled into the trial （n =113） and control （n =112） groups.They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity.Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set （81.4% vs.79.5%,P =0.712 and 95.4% vs.89.5%,P =0.143,respectively）.In both data sets,noninferiority of the trial group was above the predefined noninferiority limit（-9.5%）.Conclusions：This study established the noninferiority ofQinming8631 DR to Talos DR.The safety and efficacy ofQinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with cardiac bradyarrhythmia.

Detection of an anti-angina therapeutic module in the effective population treated by a multi-target drug Danhong injection:a randomized trial

It's a challenge for detecting the therapeutic targets of a polypharmacological drug from variations in the responsed networks in thedfferentiated populations with complex diseases,as stable coronary heart disease.Here,in an adaptive,31-center,randomized,double-blind trial invoving 920 patients with moderate symptomatic stable angina treated by 14-day Danhong injection(DHI),a kind of polyphamacological drug with high quality control,or placebo(0.9%saline),with 76-day following-up,we firstly confrmed that DHl couldincrease the proportion of patients with clinically significant changes on angina-frequency assessed by Seattle Angina Questionnaire(ASAQ-AF220)(12.78%at Day 30,95%confidence interval[C]5.86-19.71%,P=0.0003,13.82%at Day 6C0,95%CI 6.82-20.82%,P=0.0001and 8.95%at Day 90,95%CI 2.06-15.85%,P=0.01).We also found that there were no significant differences in new-onset major vascularevents(P=0.8502)and serious adverse events(P=0.9105)between DHl and placebo.After performing the RNA sequencing in 62 selectedpatients,we developed a systemic modular approach tp identfy differentilly expressed modules(DEMs)of DHI with the Z_(summay)valueless than 0 compared with the control group,calculated by weighted gene co-expression network analysis(WGCNA),and sketched out thebasic framework on a modular map with 25 functional modules targeted by DII.Furthermore,the effective therapeutic module(ETM),defined as the highest corelation value with the phenotype alteration(SAQ-AF,the change in SAQ-AF at Day 30 from baseline)calculatedby WGCNA,was identifed in the population with the best effect(ASAQ-AF240),which is related to anticoagulation and regulation ofcholesterol metabolism.We assessed the modular flexbility of this ETM using the global topological D value based on Euclidean distance,which is corelated with phenotype alteration(r^(2):0.8204,P=0.019)by linear regression.Our study identified the ant-angina therapeuticmodule in the effective population treated by the multi-target drug.Modular methods facilitate the discovery of network pharmacologicalmechanisms and the advancement of precision medicine.(ClinicalTrials.gov identifier:NCTO1681316).

Technology Development for Controlling Slab Transverse Corner Crack of Typical Micro-alloyed Steels

A mathematical model for simulating the fluid flow, heat transfer and solidification in the conventional mold and the chamfer mold, together with a finite element stress-strain model in the straightening process of both molds, were established for the typical niobium, vanadium, and titanium micro-alloyed steels. On the basis of both numerical analysis, the mold copper plate with an optimum chamfered shape was designed and applied in industrial tests. The predicted results from numerical simulation of fluid flow, heat transfer and solidification in the conven tional mold and the chamfer mold show that the increased chamfered angle leads to an approximately linear increase o[ the slab surface temperature, but it also causes strong flow near the slab corner. Very small chamfered length can lead to a significant increase of the temperature near the slab corner. However, with further increasing the chamfered length, the temperature of the slab corner increased slightly. The calculated results from the finite element analysis of stress-strain during the straightening process show that at the same slope width, the tangential strain on the slat） edges and corners is minimum when the chamfered angle is 30° and 45°, which is only 40° to 46° of rectangular slabs with the same cross-section area. At the same chamfered angle of 30°, when the chamfered length is controlled between 65-85 mm, the tangential strain on the part of the slab edges and corners is relatively smaller. Industrial test results show that the slab corner temperature at straightening segment increases about 100 ℃ by using chamfer mold compared to the conventional molds. The slab transverse corner cracks have been reduced more than 95° in comparison with those in the conventional mold.

Numerical Simulation of Electromagnetic Field and Flow Pattern in a Continuous Slab Caster with In-roll Type Strand Electromagnetic Stirring

The electromagnetic field and flow analysis model were developed to simulate the electromagnetic field and the flow pattern in a vertical curved continuous slab caster with the in-roll type strand electromagnetic stirring. The transient electromagnetic field distribution and the induced electromagnetic force were numerically described. The effects of stirring current, stirring frequency, and different stirrer configurations on the electromagnetically driven flow field in the strand were investigated and the optimization of the stirring parameters was discussed by performing a relative comparison of numerical results. Results show that the in-roller type strand electromagnetic stirrer （S- EMS） pair generates the fluctuating magnetic fields, penetrating through the cast slab and periodically parallel shift- ing along the slab wide face w!th time evolution. The transient induced electromagnetic forces travels toward the magnetic flux shifting direction, Different stirring parameters （i. e. current and frequency） and stirrer configurations affect the stirring strength and the flow rbcirculation pattern in the strand, which are closely related to metallurgical performances of the stirrers. There is an optimum frequency to obtain the maximum stirring. The present model pro vides a relatively theoretical insight into the in-roll type strand electromagnetic stirring system for best operating.

Numerical simulation of 3D electromagnetic–thermal phenomena in an induction heated slab

A mathematical model was developed to get an insight into 3D electromagnetic–thermal phenomena in an induction heated steel slab with a large width/thickness ratio by solving a fully coupled Maxwell equations and energy conservation equation.The spatial heat radiation between the slab surface and the refractory wall in an induction furnace was considered.The electromagnetic induction and temperature distribution features inside the slab with time evolution were described.The effects of electromagnetic induction parameters,thermal conductivity of the material and process parameters on the induction heating process were theoretically examined.Numerical results show that the spatial distribution of induction heat generation inside the slab is non-uniform.The high work frequency and the low heat conductivity of slab increase the non-uniformity of slab induction heating process.The radiative heat loss and heat transfer between the slab and the metal parts used for holding the slab have an important effect on the slab surface temperature.It is necessary to separately control the current input in the multi-layer coil windings along the height direction of furnace and adopt the multi-step heating strategies with time evolution to improve the homogenization of the slab temperature.

Oxidation Behavior of Fe-based Amorphous Ribbons

The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380℃ in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy （XPS） and scanning electron micros- copy （SEM）. The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O3 , SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impu-rities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B elemaent was oxidized firstly compared with other elements. More- over, the oxidation deoths of the B2O3 and SiO2 were larger than that of Fe2O3.