GPS与测距法的融合模型在机器人导航中的实现

分析了GPS信号的误差对移动机器人定位精度的影响。提出了GPS信号与测距法的融合模型。即通过计算机器人当前位置估计值与GPS信号值的欧几里德距离d，得出融合系数β，β值的大小反映了此时GPS信号与测距法融合时各自所占的比值。该融合模型保证了GPS信号误差对移动机器人的位置估计的影响降到最低。从仿真结果看出，当GPS信号发生突变时，该融合模型仍能提供相对准确的位置估计。在实验中还采用了不断优化、调整方向角并设置假想目标位置的导航算法，从而使得机器人在接近目标位置时不会迷失方向而达到理想的目标位置。试验结果表明：机器人的定位精度有很大提高，在自动导航时其行驶轨迹控制在5cm～10cm的误差范围内。     

APPLICATION OF CIRCUIT SIMULATION IN HARDWARE DESIGN FOR ELECTRONIC CONTROL HIGH PRESSURE COMMON-RAIL FUEL SYSTEM OF DIESEL ENGINE

By means of circuit simulation,hardware of electronic control unit (ECU) of high pressure common-rail electronic control fuel system for diesel engine is designed.According to the system requirements for hardware of ECU,signal-processing circuit of variable reluctance (VR) sensor,filter circuit for input signal,high voltage power circuit and driver and protection circuit of solenoid are simulated as emphases.Difficulties of wide scope of VR sensor output signal,efficiency of high voltage power and reliable and swift driver of solenoid are solved.The results of simulation show that the hardware meets the requirement of the fuel system.At the same time,circuit simulation can greatly increase quality of the design,alleviate design labor and shorten design time.     

钽涂层多孔钛合金支架的制备与表征

钽金属是一种理想的医用金属材料,能够与人体软/硬组织发生整合。利用化学气相沉积方法,在可控多孔结构的Ti6Al4V合金支架表面沉积涂覆钽金属涂层,使其同时具备理想的三维孔隙结构和力学相容性,以及钽金属优异的生物学性能。研究结果显示,多孔钛合金支架表面涂层前后色泽发生明显变化,涂层后支架呈现钽金属色泽。扫描电镜和XRD分析进一步证明了多孔钛合金支架表面沉积物为钽金属。与美国Zimmer公司生产的多孔钽小梁金属相比,钽涂层多孔钛合金支架具备与人体皮质骨更相似的弹性模量和抗压强度,是一种理想的骨修复替代物。     

高硫铝土矿浮选脱硫-串联法生产氧化铝工艺研究

采用浮选脱硫-串联法生产氧化铝工艺对高硫铝土矿进行处理,脱硫铝土矿综合样硫含量为0.26%,氧化铝回收率为99.02%。拜耳法溶出时氧化铝相对溶出率为96.02%。碱石灰烧结时氧化铝、氧化钠的净溶出率分别为90.38%、97.11%,工艺技术指标较好。     

Synthesis and photovoltaic properties of two new unsymmetrical zinc-phthalocyanine dyes

Two new soluble unsymmetrical zinc-phthalocyanine derivatives (PC-HY1, PC-HY2) with D-π-A structure bearing three tert-butylphenyl or tert-butylthienyl groups and cyanoacrylic acid groups were synthesized through a low-cost “anhydride” method. The photophysical, electrochemical and photovoltaic properties of the phthalocyanine derivatives were studied. The two phthalocyanine derivatives showed strong and broad absorption in the UV and red/near-infrared (IR) region, especially for PC-HY2. The electrochemical properties indicated that the two phthalocyanine derivatives are latent materials for dye-sensitized solar cells. Under the illumination of AM 1.5, 100 mW cm⁻², dye-sensitized solar cells based on PC-HY1 and PC-HY2 showed power conversion efficiency (PCE) of 0.79% and 1.09%, respectively.     

Influence of welding thermal cycles on microstructure and pitting corrosion resistance of 2304 duplex stainless steels

Different welding thermal cycles from single-pass to triple-pass were performed on two kinds of 2304 duplex stainless steel through Gleebe thermal–mechanical simulator. The corresponding microstructure was observed, while the pitting corrosion resistance was investigated in 1.0 M NaCl by potentiostatic critical pitting temperature (CPT). The results showed that single-pass welding deteriorated microstructure and pitting corrosion resistance significantly. As the welding pass increased, the ferrite content decreased and CPT increased. However, CPT was still lower than that of the base metal. Nitride precipitated at the boundary between ferrite and austenite phase for low-alloyed 2304 after the single-pass welding thermal cycle.     

Microstructure and Properties of SAE 2205 Stainless Steel After Salt Bath Nitrocarburizing at 450 °C

Nitrocarburizing of the type SAE 2205 duplex stainless steel was conducted at 450 °C, using a type of salt bath chemical surface treatment, and the microstructure and properties of the nitrided surface were systematically researched. Experimental results revealed that a modified layer transformed on the surface of samples with the thickness ranging from 3 to 28 μm changed with the treatment time. After 2205 duplex stainless steel was subjected to salt bath nitriding at 450 °C for time less than 8 h, the preexisting ferrite zone in the surface transformed into austenite by active nitrogen diffusion. The main phase of the nitrided layer was the expanded austenite. When the treatment time was extended to 16 h, the preexisting ferrite zone in the expanded austenite was decomposed and transformed partially into ε-nitride precipitate. When the treatment time extended to 40 h, the preexisting ferrite zone in the expanded austenite was transformed into ε-nitride and CrN precipitate. Further, a large amount of nitride precipitated from preexisting austenite zone. The nitrided layer depth thickness changed intensively with the increasing nitriding time. The growth of the nitride layer takes place mainly by nitrogen diffusion according to the expected parabolic rate law. The salt bath nitriding can effectively improve the surface hardness. The maximum values measured from the treated surface are observed to be approximately 1400 HV_0.1 after 8 h, which is about 3.5 times as hard as the untreated material (396 HV_0.1). Low-temperature nitriding can improve the erosion/corrosion resistance. After nitriding for 4 h, the sample has the best corrosion resistance.     

Microstructure and Tribological Properties of WC-CeO2/Ni- base Alloy Composite Coatings

运用等离子喷涂技术在7005铝合金表面制备了WC和CeO2颗粒协同增强镍基合金复合涂层,研究了该复合涂层的微观结构和摩擦学性能。结果表明:加入CeO2颗粒细化了复合涂层的显微组织,使WC增强颗粒从圆形变为不规则多边形,并降低了其脱碳分解程度。不同PV值摩擦条件下,WC-CeO2/镍基合金复合涂层的摩擦系数和磨损失重均低于WC/镍基合金复合涂层和镍基合金涂层。PV值小于3.36 N·m/s时,复合涂层磨损表面的最大接触应力低于其弹性极限接触应力,主要发生微观切削磨损和疲劳磨损;PV值大于3.36N·m/s后,磨损表面的最大接触应力超过其弹性极限接触应力,接触温度也急剧上升至648℃,磨损表面出现明显的塑性变形和脱落,其磨损机制变为多次塑变磨损、磨粒磨损和粘着磨损,并伴有氧化磨损。     

Anisotropic elastic properties of thermal spray coatings determined via resonant ultrasound spectroscopy

It is difficult to determine the elastic properties of thermal-sprayed ceramic and metallic coatings owing to the microstructural complexity, sample size and geometry, heterogeneity and availability of suitable techniques. Furthermore, the splat-based build-up of the coating results in transverse anisotropy in the elastic properties. This work reports on such anisotropic elastic properties of these coatings determined by resonant ultrasound spectroscopy. This approach, along with the analysis presented, enables the elastic properties to be determined for the first time as a function of direction and temperature, essential information for design. Coating systems investigated include plasma-sprayed yttria stabilized zirconia and nickel. An additional nickel coating deposited by the high-velocity oxygen-fuel process was also investigated and compared with the plasma-sprayed coating. Average Young’s moduli of the coatings were independently measured by indentation. The elastic properties determined enabled the coating microstructure–elastic property relationships to be described.