机-气复合式胸腔模拟器建模与仿真

针对现有胸腔模拟器模拟逼真度不高等问题,研制一种新型机-气复合式胸腔模拟器。分别建立了主胸骨模拟器和肋骨模拟器数学模型,仿真分析模拟器的半径和高度、片弹簧厚度和宽度、腔内压力和压缩位移等因素对胸腔模拟器刚度特性的影响,并实验验证了模型的有效性。结果表明:通过改变模拟器腔内压力及模拟器的半径和高度、片弹簧厚度和宽度等结构参数可分别模拟不同年龄段和不同性别的患者的胸腔刚度。研究结果可为设计新型心肺复苏教学模拟装置提供参考。     

反应式腹部触诊模拟装置气动系统的研究

根据诊断学中腹部触诊教学的要求,设计了一种新型的反应式腹部触诊模拟装置气动系统,研制了模拟装置的气动驱动器,设计了系统控制结构及控制算法,实验研究了模拟装置气动系统的控制特性和机械特性。结果表明:该系统能实现对气动驱动器内部压力及其硬度的控制,可模拟受训者进行腹部触诊时的感觉。该研究将为设计新型的具有反应式的临床教学装置提供依据和参考。     

抽油杆柱动力屈曲模拟装置液压加载系统设计与性能仿真

为模拟抽油杆柱受轴向外载荷产生的动力屈曲和横向振动现象,设计一种新型的基于程序控制的液压加载模拟装置。基于液压压力闭环控制方式,利用PLC输入设定值调节比例溢流阀开口度,控制系统的压力,通过压力传感器的检测与变送,将液压系统的压力反馈回PLC,从而控制连续变化的系统压力,以满足设计需求。使用MATLAB中的Simulink模块建立液压系统的数学模型,仿真得到比例溢流阀的性能曲线并验证了此液压闭环控制系统模拟装置的稳定性和可行性。     

新型高效电动静压飞行模拟器运动系统

现代飞行训练模拟器必须是具备高动态响应的长行程的六自由度运动系统。以Stewart六自由度运动平台所形成的飞行训练模拟器的电液伺服系统是用电液伺服阀控制的即为阀控系统,功率损失很大,效率很低,系统中产生的热量需要很大的冷却装置,这又需要浪费附加功率。介绍了一种新型高效电动静压飞行模拟器运动系统,该飞行模拟器的电液伺服系统中不用电液伺服阀,而是采用交流伺服电动机直接驱动定量泵的泵控系统。交流伺服电动机按外部指令信号可实现变向、变速、变转矩的伺服驱动;同时,在系统上采用蓄能器可以实现能量回收和保压。在2008年交付使用的波音787飞行训练模拟器采用了该高效电动静压运动系统。     

直升机悬停救助模拟器工作空间分析

直升机悬停救助模拟器用于在实验室中模拟训练救生人员在恶劣海况进行的直升机救助任务,Stewart并联机构因其刚度大、承载能力强、精度高等优点,被用做直升机模拟舱的动感产生装置。确定工作空间的边界一直是并联机构研究的重要内容,为保证直升机悬停模拟的运动参数不超过平台最大边界范围,需要对其工作空间进行计算和分析。以直升机悬停救助模拟系统的Stewart机构为研究对象,结合直升机悬停救助模拟器的特殊应用场景,提出一种将运动学正解和凸包算法相结合的Stewart机构工作空间计算方法,该方法具有运算准确、速度快等优点。最后,通过实验验证,该方法用于对直升机悬停模拟器在不同海况下运动状态的干涉检测具有良好的效果。     

油液抽真空除气装置的设计及仿真分析

根据亨利定律设计了一种液压油抽真空除气装置,用以提高液压油的体积弹性模量,能有效地改善液压系统的传动刚度和精度.在AMESim仿真软件平台上进行了该装置平衡压力油箱压力的仿真分析,结果表明该装置中的活塞式蓄压器能有效地起到稳定油箱压力、吸收脉动的作用.     

速度滑冰力量训练器液阻系统的设计及分析

速度滑冰力量训练器一直都是速度滑冰运动员训练过程中的一个短缺,研制一种新型的、能适应运动员训练的体育器材十分必要.针对这个问题,对一种新型速度滑冰力量训练器的阻力施加装置进行了设计,并在AMESim环境下建立了该阻力施加装置的仿真模型,对影响该训练器阻力大小的因素进行了仿真,验证了该装置的合理性,为该训练器及其他装置阻力施加装置的设计及分析提供了理论依据.     

速度滑冰力量训练器液阻系统的设计及分析（英文）

速度滑冰力量训练器一直都是速度滑冰运动员训练过程中的一个短缺,研制一种新型的、能适应运动员训练的体育器材十分必要。针对这个问题,对一种新型速度滑冰力量训练器的阻力施加装置进行了设计,并在AMESim环境下建立了该阻力施加装置的仿真模型,对影响该训练器阻力大小的因素进行了仿真,验证了该装置的合理性,为该训练器及其他装置阻力施加装置的设计及分析提供了理论依据。     

飞行模拟器逼真度评估方法研究进展

飞行模拟器作为良好的地面模拟仿真设备,具有许多优良的特性。借助飞行模拟器可以有效地进行飞行特性研究和飞行训练。在设计制造时,需要对模拟器进行评估以满足研究和训练要求,评估方法的研究已成为重点内容。综述了逼真度评估方法的研究现状,重点概述了结构模型方法和控制论2种方法。阐明了由于存在多种评估方法和标准,评估效果很难比较。分析了客观评估方法所面临的困难,展望了未来的研究方向。     

一种用于飞行模拟器的新型集成式静压伺服油缸

本文介绍一种新型的用于飞行模拟器运动系统的集成式静压伺服油缸。该油缸采用静压轴承和磁阻式位移传感器，可满足飞行模拟器的宽频带、高精度、低摩擦、大位移的技术要求，是一种新型的理想的驱动装置。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。