超值型32位MCU提供自定义管脚功能

技术的演进需要对许多软硬件方案进行升级,一般来说,如需升级原有的16位设计,获得更高性能和应用灵活性,设计人员不得不选择针对更加复杂应用设计的高端微控制器。为改善这种情况，微控制器供应商意法半导体（STMicroelectronics）近日发布了全新超低价格32位产品：STM32超值型（Value Line）微控制器。

The Fundamental Theorem of Ultraproducts in Lattice valued Model for L_α Logic

In this paper we add some new corcollary and theorems to [1],in particular,we show the fundamental theorem of ultraproducts in lattice valued model for L α logic. As a corollary,we get the α compactness theorem for L_α logic.

Effects of river width changes on flow characteristics based on flume experiment

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

Kinetic Study on Extraction of Red Pepper Seed Oil with Supercritical CO_2

A mathematical model for extraction of red pepper seed oil with supercritical CO2was proposed.Some factors influencing the process were investigated,including operation pressure,temperature and extraction yield Xe(%).The model was solved by the method of weighted residuals and used to simulate the process numerically.The kinetic equation is expressed as Xe16.8606exp(t/9.98177)16.95457 and the simulation results are in excellent agreement with the experimental data.The optimal operating parameters are 30 MPa,318 K and 60 min.

Dynamic analysis of subway station subjected to internal blast loading

The study was motivated by the fact that explosion inside the subway structure may not only cause direct life loss,but also damage the subway structure and lead to further loss of lives and properties.The propagation law of explosion wave in the subway station was analyzed and a simplified model of overpressure in the subway station was also proposed.Whereafter,the improved dynamic cam-clay model of soil and the concrete damaged plasticity constitutive model were used for the dynamic analysis of the subway station.Meanwhile,the influences of soil stiffness and burial depth on the dynamic response of the subway station were looked into.The results show that the multi-peak overpressure in the subway station does not appear,and large stresses concentrate on the central column and the floor slab of the subway station,so some special reinforcement measures should be taken in these parts.The effect of soil stiffness and burial depth on the stress of the central column is little;however,the effect on the stress of the station side wall is relatively obvious.

Spatio-Temporal Adaptive Super-Resolution Reconstruction Model Based on Zemike Moment for Spatial Video Sequences

Video Super-Resolution （SR） reconstruction produces video sequences with High Resolution （HR） via the fusion of several Low-Resolution （LR） video frames. Traditional methods rely on the accurate estimation of subpixel motion, which constrains their applicability to video sequences with relatively simple motions such as global translation. We propose an efficient iterative spatio-temporal adaptive SR reconstruction model based on Zemike Moment （ZM）, which is effective for spatial video sequences with arbitrary motion. The model uses region correlation judgment and self-adaptive threshold strategies to improve the effect and time efficiency of the ZM-based SR method. This leads to better mining of non-local self-similarity and local structural regularity, and is robust to noise and rotation. An efficient iterative curvature-based interpolation scheme is introduced to obtain the initial HR estimation of each LR video frame. Experimental results both on spatial and standard video sequences demonstrate that the proposed method outperforms existing methods in terms of both subjective visual and objective quantitative evaluations, and greatly improves the time efficiency.

Aeroelastic Simulation for Symmetric Manoeuvre of 123 Manager Light Plane

Expansion of computer technologies allow using numerical simulation in the early stages of aircraft design more and more often. The role of both wind tunnels and initial test flights used to verify the validity of solutions seems to be diminishing. Big systems for three-dimensional simulations of Fluid-Structure Interactions （FSI） constitute highly specialized and costly software. Most of the codes are based on many simplifications. In this paper fluid-structure interaction, taking into account the symetric manoeuvre of ultra light plane, is concerned. This phenomenon has important influence in many aeronautical applications. The method and developed system is demonstrated on ultra light I23 plane. For the first flow the comparison with experiment made in Institute of Aviation Warsaw is presented. Finally, aeroelastic simulation of full 123 aircraft configuration presents the capability of used numerical codes to analyze largescale complex geometries for manoeuvre. All computations were carried out in parallel environment for CFD mesh of order of millions tetrahedral elements.

Measurement and Comparison of Urban Haze Governance Level and Efficiency based on the DPSIR Model:A Case Study of 31 Cities in North China

In the decisive stage of developing of a moderately prosperous society in all aspects,hazy weather has become a major obstacle to the further advancement of China.Therefore,improving the level and efficiency of haze governance has become essential.Based on the DPSIR model,this paper builds a haze governance level and efficiency index system using the entropy method and the super-efficiency data envelope-analysis(DEA)model to analyze the data for 31 cities in North China from 2007 to 2016.From the aspects of spatial differences and influence factors influencing the comparative analysis,the results are as follows.(1)During the investigation period,the level and efficiency of city haze governance in North China showed a trend of fluctuation and decline,with obvious stages in their characteristics.Haze governance efficiency is much higher than its level,and its mean value reaches the DEA level which indicates that it is effective.(2)A significant regional gradient difference occurs between these two aspects.The haze governance level presents a convex distribution pattern of"east low–middle high–west low",while the haze governance efficiency presents a concave distribution pattern of"east high–middle low–west high".(3)The regression results show that economic growth has a negative effect on both haze governance level and efficiency.By contrast,the industrial structure has a positive effect on haze governance level and efficiency,but the significance of its effect on these two is different.On this basis,policy suggestions are proposed for improving the level and efficiency of haze governance in various cities in North China.

Simulation of shock wave buffet and its suppression on an OAT15A supercritical airfoil by IDDES

In the present paper,extremely unsteady shock wave buffet induced by strong shock wave/boundary-layer interactions (SWBLI) on the upper surface of an OAT15A supercritical airfoil at Mach number of 0.73 and angle of attack of 3.5 degrees is first numerically simulated by IDDES,one of the most advanced RANS/LES hybrid methods.The results imply that conventional URANS methods are unable to effectively predict the buffet phenomenon on the wing surface;IDDES,which involves more flow physics,predicted buffet phenomenon.Some complex flow phenomena are predicted and demonstrated,such as periodical oscillations of shock wave in the streamwise direction,strong shear layer detached from the shock wave due to SWBLI and plenty of small scale structures broken down by the shear layer instability and in the wake.The root mean square (RMS) of fluctuating pressure coefficients and streamwise range of shock wave oscillation reasonably agree with experimental data.Then,two vortex generators (VG) both with an inclination angle of 30 degrees to the main flow directions are mounted in front of the shock wave region on the upper surface to suppress shock wave buffet.The results show that shock wave buffet can be significantly suppressed by VGs,the RMS level of pressure in the buffet region is effectively reduced,and averaged shock wave position is obviously pushed downstream,resulting in increased total lift.

Numerical Analysis of Flow in Ultra Micro Centrifugal Compressor -Influence of Meridional Configuration

A single stage ultra micro centrifugal compressor constituting ultra micro gas turbine is required to operate at high rotational speed in order to achieve the pressure ratio which establishes the gas turbine cycle. As a conse- quence, the aerodynamic losses can be increased by the interaction of a shock wave with the boundary layer on the blade surface. Moreover, the centrifugal force which exceeds the allowable s^ress of the impeller material can act on the root of blades. On the other hand, the restrictions of processing technology for the downsizing of im- peller not only relatively enlarge the size of tip clearance but also make it difficult to shape the impeller with the i three-dimensional blade. Therefore, it is important to establish the design technology for the impeller with the two-dimensional blade which possesses the sufficient aerodynamic performance and enough strength to bear the centrifugal force caused by the high rotational speed. In this study, the flow in two types of impeller with the two-dimensional blade which have different meridional configuration was analyzed numerically, The computed results clarified the influence of the meridional configuration on the loss generations in the impeller passage.

Evaporation of liquid fuel droplet at supercritical conditions

A comprehensive analysis of liquid fuel droplet evaporation at supercritical conditions is performed.The numerical model is based on complete time-dependent conservation equations,with a full account of variable thermophysical properties and vapor-liquid interfacial thermodynamics.And the model employs the Peng-Robinson(PR)equation of state(EOS).As a specific example,problems involving n-heptane droplet in nitrogen gas are investigated.The results indicate that the increase of ambient pressure and temperature results in the increase of surface temperature rise rate and surface regression rate.The transition from subcritical state to supercritical state can occur at the droplet surface when the droplet evaporates in a strongly supercritical environment.