油压机智能转速感应控制系统研究

针对传统油压机普遍存在运行功率大于生产需求功率的现象,在工频状态下空载运行和无功运行对能源造成严重浪费,提出一种基于负荷极限控制的油压机电机智能转速感应控制方法,将基于PLC的PID控制策略运用到油压机电机变频调速中,克服了油压机作业循环的负载多变工况存在着的大惯性、高非线性、大滞后等不利因素。通过现场测试,节能效果达到25%,同时电机变频调速转速变化更加平滑迅速,提高了系统稳定性,满足了油压机变负载工况电机转速的实时调节要求。     

张紧器液压与驱动系统节能分析

铺管船用张紧器属于海上作业设备,要求其在工作过程中尽量减少能耗。对张紧器液压夹紧和电机驱动系统进行节能设计;在液压系统中动力源是液压系统的主要能耗因素,通过分析采用A7V.80.EL型高效、节能、大功率的复合变量泵来匹配液压系统达到节能的目的;在交流伺服电机驱动系统中,根据大功率电机的特点采用变频器对电机进行启停控制,减小启动电流实现节能,同时在电机的运行过程中,通过对功率因数进行模糊控制达到节能目的,并通过试验证明系统节能效果。     

锥阀滑阀组合控制的油压机液压系统改造

本文对油压机液压系统进行了改造,主油泵改用定级变量轴向柱塞泵,降低能耗;采用锥阀滑阀的组合控制方式,解决了原油压机主油缸压力低,系统泄漏严重的问题,同时采用集成阀块连接方式,简化了系统及管路连接,减少泄漏点,改造后油压机使用情况良好。     

铝加工企业工业炉窑节能新方法

提高加热速度是降低工业炉窑能耗的重要手段，介绍了两种节能新方法，主要是在温控系统设计中，采用炉气低温点温度或被加热制品和炉气的综合温度作控制加热过程的反馈信号，从而增强其控制作用，达到提高加热速度的目的。     

一种优化的冲压线主电机节能控制方式

<正>作为冲压车间最大的能耗来源,生产设备的能耗主要为冲压车间内部的压力机能耗,压机主电机为最主要的能耗设备。本文提出了一种优化的冲压线主电机节能控制方式,通过主动和人工两种方式去降低冲压线压机的待机时主电机转速,从而达到降低待机能耗的效果。经验证,在满足产线生产工艺需要的同时,每月能有7%的能源节约。     

工业机器人工作过程中能耗最小控制策略

针对工业机器人作业过程中能耗高的问题,提出了一种工业机器人的能耗最小控制策略,有效降低六自由度串联工业机器人在指定轨迹下匀速工作过程中的能耗。在工业机器人腰部、大臂、小臂进行动力学建模基础上,针对机器人的腰关节、肩关节、肘关节等能耗较大关节的驱动电机建立其能耗模型。通过动力学模型和能耗模型推导出机器人目标能量函数,根据约束条件提出了机器人能耗最小控制策略。通过测量机器人各个关节不同转动速度时的电机的输入功率,理论能耗与实验的对比,验证了控制策略的有效性。该控制策略可以有效降低工业机器人的作业能耗,节能增效,并对工业机器人具有普适性。     

水压机改油压机的关键技术及应用

水压机的控制精度较差,普遍存在操作方式落后、产品尺寸精度难以控制、产品成品率低、设备故障率高、能耗高及系统泄漏严重等问题。对老旧水压机主机、液压和控制系统进行现代化改造和升级,将水压机改造成油压机,全面提升压机性能,提高生产效率,降低维护维修成本和能耗,成为诸多水压机使用厂家的迫切需求。介绍了水压机改油压机技术的优点和发展现状,重点叙述了水压机改油压机的关键技术。通过水改油工程实践表明:将老旧水压机改造升级成为油压机,能全面提升设备性能,提高生产效率;并可应用新的功能和工艺,有利于提升产品质量和开发新产品;同时,节能降耗效果明显,经济效益显著。     

压铸机节能化再制造

交流伺服电机+定量油泵的伺服直驱泵控液压系统具有节能、高效、可靠等一系列优点,运用该技术对某型号800t的传统卧式冷室压铸机进行节能化改造,建立了改造后的压铸机能耗仿真模型并进行能耗仿真和能耗实验。实验结果表明:改造后的压铸机节能达到45%以上,生产效率提高5%。对其节能机理进行分析的结果表明:伺服直驱泵控液压驱动技术能实现输入能量与负载的主动适配,适应执行机构变化的速度和压力要求,减少了阀控系统不可避免的节流损耗和溢流损耗;生产效率提高的原因在于蓄能器充液阶段和空行程阶段速度加快,减少了工作循环时间。     

12MN/20MN框架双动油压机伺服节能改造

介绍了12MN/20MN框架双动油压机采用伺服电机驱动双联泵取代原三相异步电动机驱动恒功率变量泵的节能改造方案,并对伺服驱动控制的应用和机床动作进行了介绍。同时该机床增加有平衡缸装置,提高了机床的工作效率。通过改造,可实现节能47%,噪声明显降低,连续运行4小时油温在环境温度基础上仅升温15℃。     

伺服系统转动惯量辨识及控制器PI参数优化

在机器人运行时,为了使伺服电机在最优性能下达到目标速度、在工作过程中有着更强的抗扰动能力,并避免出现震荡、谐振的状况,从而造成机器人运行时动态稳定性严重降低。提出一种基于非线性动态学习因子的粒子群优化算法,对普通粒子群优化算法进行改进。该算法以伺服系统控制模型中的速度控制器为核心,实时辨识负载转动惯量值,使伺服系统内部控制参数根据实际工况调节;运用该辨识值,通过计算得到速度控制PI参数值,并实时修正速度控制器PI参数值。MATLAB/SIMULINK仿真结果表明,与传统的粒子群优化算法相比,无论在电机启动过程中、还是负载扰动下,该方法都具有更快的响应速度、更高的控制精度以及更强的抗干扰能力。     

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.     

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.     

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).     

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.