基于LabVIEW的电动伺服阀加载测控系统

针对传统电磁阀电磁滞后等不足,用某型电动伺服阀取代电磁阀以满足姿轨控发动机的高推力、高精度要求。为对其进行半实物仿真测试,基于伺服旋转电机加滚珠丝杠,设计了电动伺服阀综合性能加载测控系统。硬件采用先进的PXI总线搭建,软件采用Lab VIEW作为上位机平台,具体设计了主程序、实时程序及通信方式;为抑制伺服阀的位置扰动并提高加载精度,提出一种前馈位置补偿和力闭环PID控制的方法。实验结果表明:用该系统有效地测试了电动伺服阀承受外载能力及其输出位移精度,且满足"双十指标"。     

基于虚拟仪器的伺服阀测试系统设计与实现北大核心

液压伺服阀具有响应速度快等优点,其性能直接影响设备的整体性能。为保证伺服阀的质量和设备的正常的运行,设计一套基于虚拟仪器的伺服阀性能测试系统。利用该系统对伺服阀性能参数进行测试。结果证明:相比于传统的基于VB/CAT的伺服阀性能测试系统,所设计的系统具有设备组成简单、编程简单、测试精度高、响应性好等优点,能够可靠地完成伺服阀主要性能的测试,保障设备的安全运行。     

基于LabVIEW和PXI的电动直线加载系统

针对某型航天用电动伺服阀,提出一种基于Lab VIEW和PXI的电动直线加载系统(ELLS)以测试电动伺服阀的实际推力。机械结构上采用大导程精密滚珠丝杠副作为力矩/力转换元件,并采用PXI总线搭建了ELLS的硬件架构,选用Lab Vl EW软件开发了上位机软件平台;为抑制ELLS多余力,提出一种基于电流内环、位置内环和力外环的三闭环复合控制策略,并在电流内环中应用基于复矢量PI控制的电流耦合补偿方法。最后,搭建了ELLS,并进行了信号跟踪实验,结果表明ELLS以较高精度有效地测试了电动伺服阀,所提控制方法有效抑制了多余力。     

基于LabVIEW和USB总线技术的测试系统

基于Lab VIEW和USB总线技术进行数据采集与处理系统的设计,并进行实验验证。针对设备测试应用中信号类型多、通信接口种类繁杂的现状,对目前应用的ATS通用信号调理平台进行深入研究。提出将Lab VIEW和USB总线技术应用于信号调理平台的思想,成功地解决了实际设备检测系统中的信号调理平台的程控性问题。     

基于LabVIEW工业机器人自动分拣系统设计

自动分拣系统是大多数流水生产线上的一个重要环节。基于机器视觉的机器人分拣则有着适应范围广、随时变换作业对象和变换分拣工序的优势。设计基于Lab VIEW软件控制的工业机器人自动分拣系统,采用Lab VIEW软件编程、设计原型。测试和实验证明,系统能够稳定地实现物料的迅速识别和自动分拣。     

基于液压伺服阀动态特性测试的改进型逆重复伪随机算法

运用一种改进型的逆重复伪随机算法，结合先进的VXI总线仪器，成功地实现了液压伺服阀动态性能的测试，实践证明了这种方法的有效性。     

基于VXI总线虚拟仪器液压伺服阀动态特性测试实验台的逆重复伪随机算法

为了提高液压伺服阀动态特性测试的精度与速度,针对液压伺服阀实验台设计了相应的逆重复伪随机算法,并用VXI总线虚拟仪器进行了实际测试。结果表明,该算法相比于传统的方法具有实验时间短和测试精度高的特点。     

基于VXI总线虚拟仪器液压伺服阀动态

为了提高液压伺服阀动态特性测试的精度与速度,针对液压伺服阀实验台设计了相应的逆重复伪随机算法,并用VXI总线虚拟仪器进行了实际测试.结果表明,该算法相比于传统的方法具有实验时间短和测试精度高的特点.     

基于LabVIEW的全液压制动测试系统的设计

为了实现对全液压制动系统的压力、流量、温度等参数的自动检测,基于模块化和虚拟化的思想,以Lab VIEW为软件平台,以NI的数据采集卡等为硬件基础,实现对全液压制动系统的数据采集和数据存储。用虚拟仪器代替了实际物理仪器,降低了测试系统的成本,缩短了测试试验的时间。     

被动式力伺服系统的多余力抑制方法

为测试某型电动伺服阀是否满足姿轨控发动机的高推力、快响应要求,采用伺服旋转电机与精密滚珠丝杠的方式,研发了一种被动式力伺服系统(PFSS)。硬件上采用先进的PXI总线搭建了PFSS,软件上采用Lab VIEW作为PFSS的上位机平台;针对多余力严重干扰PFSS加载精度的问题,为抑制多余力,基于耦合被测阀的数学模型,提出一种多闭环复合控制方法,并引入了位置闭环补偿控制,并采用复矢量PI控制应用于电流内环,提出一种模糊自适应整定PID控制方法应用于力外环。实验结果表明,所提控制方法有效地抑制了多余力,满足了"双十指标"。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.