摘要：Convection heat transfer coefficient and air pressure drop in sinter layer are important factors for the design of sinter cooling craft. Due to the lack of necessary data, the two parameters are studied by experimental method. The experimental results show that heat conduction of sinter impacts the measurement of convection heat transfer coefficient. Convection heat transfer increases with the increase of air volumetric flow rate. Sinter layer without small particles(sample I) gives higher convection heat transfer coefficient than that with small particles(sample II). Under the considered conditions, volumetric convection heat transfer coefficient is in the range of 400-1800 W/(m3·°C). Air pressure drop in sinter layer increases with the increase of normal superficial velocity, as well as with the rise of air temperature. Additionally, air pressure drop also depends on sinter particle size distribution. In considered experimental conditions, pressure drop in sinter sample II is 2-3 times that in sinter sample I, which resulted from 17% small scale particles in sinter sample II.

摘要：A compact high-voltage repetitive nanosecond pulse generator(HRNPG)was developed for studying the technology of repetitive nanosecond pulse technology and its related *** HRNPG mainly consists of a repetitive charging module,a Tesla transformer and a sharpening *** its voltage lower than 1 kV,the primary repetitive charging circuit comprises two fast thyristors as its low-voltage *** spiral Tesla transformer acts as the main step-up component,and its peak transformation ratio is designed to be more than 100.A self-breakdown spark switch,*** sharpening switch,is used to sharpen the output of the transformer and to generate nanosecond *** HRNPG prototype is capable of generating pulses of 100 kV in peak with rise time 30 ns and the maximum repetition rate of 500 Hz on a 6 k *** results show,without any magnetic core,the developed Tesla transformer prototype can easily output high voltage while keeping itself small in size and light in weight,which is of significance for the compactness and portability of the pulse *** N2-insulated spark switch operated well at voltage close to 100 kV and the repetition rate within several hundreds of hertz.

摘要：Modular technology can effectively support the rapid design of products, and it is one of the key technologies to realize mass customization design. With the application of product lifecycle management(PLM) system in enterprises, the product lifecycle data have been effectively managed. However, these data have not been fully utilized in module division, especially for complex machinery products. To solve this problem, a product module mining method for the PLM database is proposed to improve the effect of module division. Firstly, product data are extracted from the PLM database by data extraction algorithm. Then, data normalization and structure logical inspection are used to preprocess the extracted defective data. The preprocessed product data are analyzed and expressed in a matrix for module mining. Finally, the fuzzy c-means clustering(FCM) algorithm is used to generate product modules, which are stored in product module library after module marking and post-processing. The feasibility and effectiveness of the proposed method are verified by a case study of high pressure valve.

摘要：A new purification process was developed to remove impurities in metallurgical grade silicon （MG-Si） by electromagnetic induction slag melting （EISM）. Vacuum melting furnace was used to purify boron in different slag systems. The results show that the removal effect in SiO2-CaO-Al2O3 systems is better than that in other slag systems by EISM. The boron content in MG-Si is successfully reduced from 1.5× 10^-5 to 0.2× 10^-5 during EISM at 1 823 K for 2 h. Meanwhile, Al, Ca and Mg elements in MG-Si are also well removed and their removal efficiencies reach 85.0%, 50.2% and 66.7%, respectively, which indicates that EISM is very effective to remove boron and metal impurities in silicon.

摘要：An effect of the swirling flow on the combustion performance is studied by the computational fluid dynamics(CFD) in a micro-gas turbine with a centrifugal compressor, dump diffuser and forward-flow combustor. The distributions of air mass and the Temperature Pattern Factor(as: Overall Temperature Distribution Factor-OTDF) in outlet are investigated with two different swirling angles of compressed air as 0° and 15° in three combustors. The results show that the influences of swirling flow on the air distribution and OTDF cannot be neglected. Compared with no-swirling flow, the air through outer liner is more, and the air through the inner liner is less, and the pressure loss is bigger under the swirling condition in the same combustor. The Temperature Pattern Factor changes under the different swirling conditions.

摘要：Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under *** a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on *** rationality of the established model was thoroughly *** horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently *** safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)*** optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction *** of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare *** addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,*** speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track *** running safety of the train was improved by increasing the fastener stiffness and isolation layer friction *** the rail fastener lateral stiffness of 60 kN/mm and isolat

摘要：There is a lack of thermophysical data of heat transfer oil and nano-oil in the high temperature range of 50-300 ℃ for designing and developing heat transfer oil furnace and its heating systems. In the present study, the thermal conductivity values of heat transfer oil and TiO2 nano-oil in the above high temperature range were measured by a newly developed high-temperature thermal conductivity meter. Based on the principle of least square method, the thermal conductivity values obtained from experiments were fitted separately, and the correlation between thermal conductivity and temperature of heat transfer oil and TiO2 nano-oil was obtained. The results show that the thermal conductivity and the increased percentage of thermal conductivity of TiO2 nano-oil are proportional to the increase of particle size and mass fraction of nanoparticles, but thermal conductivity is in reverse proportion to the increase of temperature and the increased percentage of thermal conductivity is less affected by temperature.

摘要：For a class of linear discrete-time systems that is subject to randomly occurred networked packet loss in industrial cyber physical systems, a novel robust model predictive control method with active compensation mechanism was proposed. The probability distribution of packet loss is described as the Bernoulli distributed white sequences. By using the Lyapunov stability theory, the existing sufficient conditions of the controller are derived from solving a group of linear matrix inequalities. Moreover, dropout-rate with uncertainty and unknown dropout-rate are also considered, which can greatly reduce the conservativeness of the controller. The designed robust model predictive control method not only efficiently eliminates the negative effects of the networked data loss in industrial cyber physical systems but also ensures the stability of closed-loop system. Two examples were provided to illustrate the superiority and effectiveness of the proposed method.

摘要：The effect of current on the morphology of Al alloy T-joint in double-pulsed metal inert gas（DP-MIG） welding process was investigated by simulation and experiment.A three-dimensional finite element model and the DP-MIG heat source of double-ellipsoidal volumetric model were developed to simulate the temperature and stress fields under different welding *** macro-morphology and microstructure of welding joints at the corresponding currents were observed in the *** results show that the best condition is at an average current of 90 A and current difference of 40 A,when the maximum temperature is 200 °C higher than the fusion points,with the temperature difference of about 100 °C and stress change of 10 MPa between thermal pulse and thermal *** these conditions,Al alloy T-joint with proper fusion condition has smooth fish-scale welding appearance and finer ***,the thermal curves and stress distribution in the experiment are consistent with those in the simulation,verifying the precision of the welding simulation.

摘要：The residence-time distribution （RTD） and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematical model as well as three-dimensional computational fluid dynamics （CFD） model was established to analyze the flow regions of feedwells on an industrial scale. The concept of RTD, although a well-known method for the characterization of mixing behavior in conventional mixers and reactors, is still a novel measure for the characterization of mixing in feedwells. Numerical simulation results show that the inlet feed rate and the aspect ratio of feedwells are the most critical parameters which affect the RTD of feedwell. Further simulation experiments were then carried out. Under the optimal operation conditions, the volume fraction of dead zone can reduce by10.8% and an increasement of mixing flow volume fraction by 6.5% is also observed. There is an optimum feed inlet rate depending on the feedwell design. The CFD model in conjunction with the RTD analysis then can be used as an effective tool in the design, evaluation and optimization of thickener feedwell in the red mud separation.