海洋废弃平台桩基拆除绳锯机液压系统可靠性研究

海洋废弃平台桩基拆除绳锯机是一种近年发展起来的新型水下切割机具,液压系统为其提供动力。可靠的液压系统是绳锯机安全、稳定工作的保障。设计了绳锯机液压系统,分析了液压系统的可靠性理论,得到了废弃平台桩基拆除绳锯机液压系统逻辑图。根据绳锯机的具体水下工作环境和条件,研究并计算了其液压系统可靠性,为绳锯机的安全稳定工作打下了一定基础。实验表明,绳锯机液压系统可靠性满足设计要求。     

海洋废弃平台桩基拆除绳锯机多扰动定位夹紧力研究

海洋废弃平台桩基拆除绳锯机是一种复杂的机电设备,夹紧力的选择,直接关系到绳锯机的安全稳定工作。分析了桩基夹紧时的截面弯矩和变形量,得到了废弃平台桩基失稳临界力计算方法。利用有限元法分析了桩基夹紧时的变形和受力。采用非线性模型求解出了不同失稳临界力条件下的夹紧瓣夹紧力。实验表明,满足桩基不同失稳临界力条件下,绳锯机夹紧装置的夹紧力能够保证绳锯机安全工作。该结果为绳锯机的水下可靠性工作打下了一定基础。     

海洋废弃平台桩基拆除绳锯机驱动组件关键参数研究

海洋废弃平台桩基拆除绳锯机是一种复杂的机电一体化设备,关键部位的密封直接决定了该设备的使用寿命。介绍了驱动轮轴承室的密封结构,分析得到了其主要部件在温度变化时的应力及尺寸变化数学模型,根据理论分析结果进行了实验研究。实验表明,温度变化对密封结构产生的影响必须要考虑,并且要对相关参数进行修正。该结果为绳锯机的密封组件关键参数选择提供了理论依据。     

海洋废弃平台桩基拆除绳锯机夹紧力的研究

介绍废弃平台桩基拆除水下绳锯机的组成和工作原理。对夹紧装置进行力学模型简化,从理论上证明绳锯机夹紧装置能够满足形封闭条件,可以使绳锯机稳定地固定在平台桩基上。分析绳锯机夹紧时的受力情况,根据最小值原理得出了绳锯机夹紧力求解的数学模型。按照水下绳锯机的实际工况对夹紧力进行求解,该结果为绳锯机的夹紧装置结构设计和液压系统设计提供理论依据。     

海洋废弃平台桩基拆除绳锯机夹紧齿优化设计研究

海洋废弃平台桩基拆除绳锯机是一种近年发展起来的新型水下作业机具,它主要由绳锯机本体和液压控制系统构成,绳锯机夹紧瓣上的夹紧齿可以使绳锯机安全、稳定地工作。介绍了夹紧齿的结构,分析得到了夹紧齿尺寸和齿周过渡曲线的优化数学模型,采用有限元法优化得到了夹紧齿关键参数。根据优化结果设计制造了夹紧齿,实验结果表明:该夹紧齿能够满足要求,为绳锯机的安全稳定工作打下了一定的基础。     

海洋废弃平台桩基拆除绳锯机切割驱动性能研究

海洋废弃平台拆除过程中可以采用绳锯机切断桩基,适当大小的切割驱动力是绳锯机安全稳定工作的前提条件.介绍绳锯机工作原理,分析绳锯机平稳运行与非平稳运行过程中的切割驱动力计算方法.根据绳锯机的一些已知设计条件,采用非平稳运行时的算法计算了绳锯机的关键驱动几何参数.实验结果表明,由此参数设计的绳锯机能够满足实际桩基切割要求,同时分析了金刚石颗粒的存在对驱动过程的影响.     

海洋废弃平台桩基拆除绳锯机夹紧力的阻抗控制策略研究

海洋废弃平台拆除过程中可以采用水下绳锯机切断桩基,适当大小的夹紧力是绳锯机安全稳定工作的前提条件。分析绳锯机夹紧力控制策略,建立绳锯机夹紧瓣夹紧桩基时的动力学方程,提出采用位置型神经网络阻抗控制方法来控制夹紧力,设计神经网络补偿器。根据绳锯机的实际工程样机,对多种情况下的力控制进行仿真研究,结果表明:位置型神经网络阻抗控制方法可以很好地补偿夹紧瓣动力学模型和位置的不确定性,适合于绳锯机夹紧力控制。     

海洋废弃平台桩基拆除绳锯机驱动系统控制研究

伴随着海洋油气田多年的开采,越来越多的废弃平台需要分解处理,切割是非常重要的一道工序。平台水下桩基切割可以采用绳锯机来完成,考虑到桩基的直径较大,研发的绳锯机切割框架包含4个绳轮,其中驱动轮为相邻两个。为了安全高效切割,必须使两个驱动轮保持同步。建立驱动轮同步工作的动力学模型,提出同步耦合控制方法。结合绳锯机的实际结构,对控制方法进行仿真分析和实验研究。结果表明:该控制方法能够满足绳锯机的水下切割要求,为绳锯机的高效稳定工作打下了一定理论基础。     

基于粒子群算法的海洋废弃平台桩基拆除绳锯机夹紧力优化

水下绳锯机可以用来完成海洋废弃平台桩基切割。绳锯机切割过程中,当水下环境发生变化时,应能够较迅速地调整夹紧力以适应环境的改变。介绍绳锯机的夹紧数学模型,根据绳锯机的实际设计条件,采用粒子群算法对夹紧力进行快速的优化求解。通过实验表明,此方法获得的夹紧力能够使绳锯机稳定地工作,并且测得了相应的动态参数。研究结果为绳锯机夹紧力的水下环境快速自适应控制提供了一定的基础。     

海洋废弃平台桩基拆除绳锯机夹紧位姿控制研究

海洋废弃平台桩基拆除绳锯机工作前需要快速固定到桩基上,这是一个复杂的位姿调整过程,需要由夹紧装置来完成,由绳锯机夹紧液压缸同步控制,使位姿调整过程安全、稳定。分析得到了位姿调整的动力学模型;采用二级控制方法设计了控制系统,其中外环采用定量反馈控制理论,内环采用基于扰动观测的理论;进行了绳锯机位姿调整实验,结果表明:控制系统在误差范围内能够使液压缸同步,进而实现了位姿调整的工程目标,该结果为绳锯机水下高效可靠地工作打下了一定的基础。     

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。     

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.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.