基于微机控制的液压冲击器（英文）

传统液压冲击器的冲击能参数调整需在2~3个挡位之间以手动操作的方式进行,且冲击能与冲击频率间的调整具有关联性。参数调整时,液压冲击器需停止工作。为改变这种状态,开发了新型基于微机控制的液压冲击器DBS300。该新型液压冲击器采用模糊控制策略实现控制,在拥有最大300 J冲击能情况下,其可实现冲击频率在0~6 Hz间的独立调整。工作中可依据每次冲击后活塞不同反弹速度引起的后部气腔压力变化率来判别被冲击物体特性的改变。依据被冲击物体特性变化,新型冲击器可对冲击能或冲击频率实现独立自我调整,由此可提高冲击破碎工作效率,并具有对冲击器载具功率特性变化的良好适应能力。     

基于AMESim的锚杆钻机液压冲击器系统建模与仿真

分析了锚杆钻机液压冲击器系统工作原理,采用AMESim软件对液压系统进行建模仿真,分别分析了泵的输入流量、冲击活塞速度和位移、冲击机构频率间的变化关系以及对冲击器性能的影响,为锚杆钻机的冲击器冲击特性研究提供了理论基础。     

基于FLOWMASTER的液压冲击器动态特性仿真研究

在分析了液压冲击器工作原理的基础上,利用一维流体仿真软件FlOWMASTER搭建了气液联合式液压冲击器的仿真模型。结合仿真结果,分析冲击活塞的运动规律以及压力、流量的变化情况,为液压冲击机构的非线性模型研究提供了参考。基于FlOWMASTER的仿真为研究液压冲击器工作机理、提高液压冲击器工作性能和优化系统参数提供了一种可行的理论方法。     

液压冲击器氮气室预充压力对冲击性能的影响研究

在分析液压冲击器工作原理及特点的基础上,建立液压冲击器系统的非线性数学模型。运用MATLAB/Simulink分别对液压冲击器的回程加速过程和冲程过程进行仿真研究,分析氮气室预充压力对冲击器冲击性能的影响程度。结果表明:氮气室预充压力过大,会导致液压油不能推动活塞进行回程,液压冲击器起动不了;压力过小,则很容易使冲击压力升不上去,冲击能小。     

基于氮气室的液压冲击器理论分析与实验研究

对带氮气室的液压冲击器的运动特性及性能参数进行了研究与设计。构建液压冲击器活塞运动的速度时间目标函数,建立了基于氮气室的活塞回程运动、冲击运动非线性数学模型,并得到了活塞运动曲线的微分方程;通过确定部分目标性能参数,从而推导出其余的性能参数,采用这种参数的设计方法,可以将机器的性能参数与运动参数联系起来,有利于确定结构参数,该方法对实际应用及理论研究具有参考价值。     

水下液压冲击器配油阀的分析

配油阀是水下液压冲击器功能实现的关键部件.通过对锥阀芯的流量进行具体分析,确定锥阀芯的锥角角度.利用"水锤效应"的分析方法,对配油阀的设计参数进行验证.根据锥阀芯和配油阀阀芯的力平衡方程,对此配油阀进行仿真分析,从液压冲击、阀口流量和力分析等方面校验了配油阀的设计合理性.     

射流冲击器性能参数的实用计算公式

利用所提出的射流冲击器性能参数实用计算公式,能据泵压及泵量变化准确地预测和控制冲击器的工作参数,以克服凭经验打钻的弊端。其精度优于阿里莫夫公式。     

氮爆式液压冲击器运动性能Simulink仿真及实验研究

为了提高氮爆式液压冲击器在公路夯实领域的冲击稳定性,建立氮爆式液压冲击器活塞回程运动、冲击运动的数学模型,并运用Simulink数值计算平台建立活塞运动的仿真模型。结果表明:冲程运动时,活塞加速度随时间单调减小;回程运动时,活塞加速度随时间先减小后增加,蓄能器氮气室和液压系统的配合明显提高了速度控制的稳定性。以应用氮爆式液压冲击器的小型破碎锤为例,实测不同液压系统压力下冲程和回程最大速度,通过与仿真结果比较,回程速度和冲程速度的相对误差分别为13.3%和2.6%。     

凿岩机冲击压力先导控制油路性能研究

凿岩机液压控制系统需根据推进和回转负载情况自动调整冲击回路的压力参数,以实现凿岩机多个运动部件间的压力流量精确匹配,从而实现高效凿岩和防空打功能。根据凿岩机冲击压力控制原理,结合实验数据建立了系统的非线性数学模型,利用方框图方法分析了先导控制回路的动态特性,找到了先导压力控制系统中结构参数、介质流动特性参数对系统工作性能的影响规律,为凿岩台车类产品开发提供参考。     

液压冲击器回程运动和冲程运动仿真研究

根据氮爆式液压冲击器的工作原理,建立液压冲击器活塞在回程加速过程和冲击过程时的动力学方程。用EASY5的General Purpose库和MATLAB的Simulink动态仿真软件包分别对液压冲击器的回程加速过程和冲程过程进行仿真研究,并将两者的仿真结果作了对比,结果基本一致,表明了回程加速运动过程中活塞加速度、速度、位移、氮气室氮气压力和系统油压的变化都与系统油泵供油量有关;冲程运动则不受系统油泵供油量影响。     

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.     

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。     

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.     

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.     

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.     

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.