基于红外路径识别的智能车控制系统设计

介绍一种基于模拟式红外光电传感器路径识别的智能车控制系统,使用飞思卡尔公司16位单片机MC9S12DG128为核心控制单元,采集红外传感器信号智能分析导引线路径信息,自动控制舵机转向,并对智能车的直流驱动电机实现PID调速控制。     

Mesh motion approach based on spring analogy method for unstructured meshes

Mesh motion strategy is one of the key points in many fluid-structure interaction problems. One popular technique used to solve this problem is known as the spring analogy method. In this paper a new mesh update approach based on the spring analogy method is presented for the effective treatment of mesh moving boundary problems. The proposed mesh update technique is developed to avoid the generation of squashed invalid elements and maintain mesh quality by considering each element shape and grid scale to th...     

H_∞ Autopilot Design for Autonomous Underwater Vehicles

The design approach of H∞ autopilot for autonomous underwater vehicles (AUVs) is proposed. Comprised by the three sub-controllers,i.e. speed,heading and depth controllers,the designed autopilot has advantage over existing H∞ control of AUVs. The overshoot in speed,heading and depth control systems under step commands is restricted by refining the weighting function for robust stability. The dynamic performance of heading and depth control systems is improved by feeding back yaw rate and pitch angle,respecti...     

核受体免疫组织化学染色时抗原修复方法的选择

目的 探讨不同抗原修复法对DA.1U大鼠肝组织内核受体检测结果的影响.方法 应用微波修复法、高压修复法、酶修复法和高压加酶修复法对DA.1U大鼠肝组织切片进行修复,然后进行免疫组化染色.结果 DA.1U大鼠肝组织内核受体LXR-α、LXR-β、PPAR-γ和FXR经高压抗原修复后,染色阳性强度较其他修复方法明显增强,而且定位较佳.结论 在核受体免疫组化染色中高压抗原修复法染色效果优于其他抗原修复法.     

苦参碱对人卵巢癌细胞增殖的影响及其机制

目的 研究苦参碱(matrine)体外培养的人卵巢癌细胞OV2008增殖的影响及相关机制.方法 采用四甲基偶氮唑蓝(MTT)比色法检测不同浓度(0、0.125、0.25、0.5、1.0,2.0、4.0 mg/mL)的苦参碱在不同的时间点(24、48、72 h)对OV2008细胞增殖的影响;采用流式细胞术(FCM)检测不同浓度的苦参碱作用于OV2008细胞48 h后细胞周期分布、凋亡率及Fas、Bcl-2蛋白的表达水平.结果 苦参碱对OV2008细胞的增殖具有明显的抑制作用,与对照组相比具有显著性差异(P<0.05或P<0.01),并呈现时间和剂量依赖性;细胞周期分析显示,随着苦参碱浓度的增高,G0/G1期细胞比例逐渐增加,S期细胞比例减小,G2/M期细胞比例无明显变化;苦参碱能够诱导细胞凋亡,且凋亡率随着苦参碱浓度的增高而升高(P<0.01);苦参碱能够上调Fas蛋白的表达(P<0.05或P<0.01),下调Bcl-2蛋白的表达(P<0.01).结论 苦参碱可显著抑制OV2008细胞的增殖,且抑制作用晕剂量和时间依赖性.苦参碱对OV2008细胞的增殖抑制作用可能与其诱导细胞周期阻滞及凋亡有关,而苦参碱诱导凋亡可能与其上调Fas蛋白表达、下调Bcl-2蛋白表达有关.     

连续配筋混凝土路面纵向钢筋荷载疲劳断裂分析

采用ANSYS非线性有限元程序,分析标准轴载作用下连续配筋混凝土路面横向开裂稳定后裂缝处纵向钢筋的塑性应变,并利用损伤理论及屈服准则推导重复荷载作用下裂缝处纵向钢筋断裂的疲劳公式,具有一定的理论和现实意义。     

Mechanical behaviors of the foot after individual releases of plantar fascia and ligaments during the balanced standing

To quantify mechanical effects of plantar fascia and ligaments on the arch structure, a 3D finite element model of the foot was created to simulate the balanced standing posture. Four cases after individual releases of plantar fascia, spring ligament, long and short plantar ligaments were simulated respectively to compare their consequences to the predictions of the intact structure. It was founded that the foot arch didn’t collapse obviously after any individual release of these structures. As plantar fascia was released, tensions of plantar ligaments were largely increased. Long and short plantar ligaments performed mutual compensation functions.     

Dynamic investigation on composite flexible multi-body system considering thermal effect

The dynamic performance of composite flexible multi-body system under the simultaneous action of thermal fields and driving constraint is analyzed. Based on strain-displacement relation of the Mindlin plate theory which includes transverse shear deformation, and considering thermal effect, variation equations of laminated plate are derived by the principle of virtual work. The finite element method is used for discretization. According to kinematics constraint relation, dynamic equations for spatial slider-crank system are established. Simulation results show that spatial deformation (torsion deformation) appears in the multi-layered composite slider-crank mechanism which is simulated with planar motions. Furthermore, the influence of coupling between thermal expansion and flexible deformations of non-symmetrical composite plates on the large overall motion under the uniform temperature field is investigated. Finally, significant change in constraint force due to the spatial deformation is shown.     

Novel mesh technique and its application in the wind field simulation for flexible spatial structure

In this paper, novel mesh techniques are proposed for wind field simulation of flexible spatial structure. For mesh generation, an interpolation strategy is presented to obtain a mesh system with variable density. Two spatial structure examples are used to examine the efficiency and applicability of this technique. Then based on the structured mesh system generated by the technique, the mesh nodal coordinates are updated to adapt the moving boundary conditions by means of the mapping interpolation functions and some examples are given to verify the effectiveness. Furthermore, the constrained counterforce distribution technique and projection interpolation strategy are developed to implement the data exchange on the interaction surface of wind and structure. Finally, the computational accuracy is numerically validated.     

Numerical analysis and experimental study of the effect of workpiece thickness on flow field in laser cutting

Based on Navier-Stokes equation and renormalization group (RNG) onflow model, the 3D symmetrical impinging jet model of laser cutting is established by adopting a taper nozzle and a convergence nozzle. Numerical simulation of gas flow in laser cutting is used to investigate the effect of workpiece thickness on flow field of assist gas in cutting slot. The isolines of static pressure as well as the distributions of static pressure and velocity are analyzed in details with different workpiece thickness, and the trend of dynamics characteristics of gas jet is shown in the study. For taper nozzles and convergence nozzles, the dynamic structure of assist gas being close to the lower surface of workpiece is exacerbated while the cutting quality and cutting efficiency become worse with the increasing of workpiece thickness. The parallel degree between assist gas and the axis of convergence nozzle is better than that of taper nozzle after the gas goes out of the nozzles. Two typical subsonic nozzles are designed for the cutting experiment at the end of the paper.