金刚石绳锯切割混凝土的锯切力实验研究

对烧结金刚石串珠绳锯在锯切混凝土过程中锯切力的变化进行了跟踪检测实验,研究了锯切力随锯切参数及锯切长度的变化规律.实验结果表明:锯切过程中,工件上所承受的锯切力(水平力Fh和垂直力Fv)随着线速度vs的提高而减低,随着进给速度vf的提高而增加.锯切力随着锯切中工件长度L的增加而增加.垂直力与水平力之间存在着良好的对应关...     

金刚石线切割单晶碳化硅锯切力的实验研究

从锯切力的角度对金刚石线锯锯切单晶SiC材料的加工过程进行了研究。得出了线速度、进给速度、线锯张紧力对锯切力的影响规律。从单位长度线锯材料去除量、锯切比能的角度讨论了锯切工艺对锯切力的影响机理。在金刚石线锯锯切单晶SiC过程中,锯切力随着线速度的增大而减小,随着进给速度的增大而增大,线速度与进给速度对锯切力的综合影响表现为:单位长度线锯材料去除量的增加会增大锯切力。单位长度线锯材料去除量对于金刚石线锯锯切单晶SiC材料的锯切比能具有显著的影响。     

锯切大理央保锯切力与锯切深度关系的研究

本探讨了锯切大理岩实验中锯切力（法向力和切向力）与锯切深度ap间关系，当锯片转速和石材进给速度一定时，随着锯切深度增加，法向与切向力呈线性增大，金刚石的承受载荷也随之增加。     

金刚石薄锯片高速锯切花岗石过程中的锯切力特性

本文对金刚石薄锯片高速锯切花岗石过程中的锯切力特性进行试验研究,在较宽的参数范围下,通过测量水平力、垂直力和主轴功率来计算切向力和法向力.对锯切力、力比、单颗金刚石承受的平均载荷进行了分析.结果显示,提高锯片的线速度使锯切力、力比和单颗金刚石磨粒承受平均载荷减小;在高速锯切时,锯切力随着锯切深度和进给速度的增加而增加,而进给速度对锯切力的明显影响要小于锯切深度,应选择小切深大进给的工艺参数组合;锯切力比随锯切深度的增加而增加,随进给速度的增加而减小;单颗金刚石磨粒承受平均载荷随着单颗粒金刚石最大未变形切削厚度的增大而线性增大.     

金刚石串珠绳锯锯切技术研究现状与发展

简要回顾了金刚石串珠绳锯的发展.根据金刚石串珠锯加工原理及特点,总结金刚石串珠绳的制备工艺及分类,分析金刚石串珠锯锯切机理.分析了串珠的磨(破)损、锯切力与加工参数的关系,认为单载荷作用时串珠磨损取决于金刚石出刃、串珠组分与锯切参数;锯切力随着进给速度与锯切长度增大而增大,随着串珠绳线速度增加而降低.最后,指出金刚石串珠绳锯亟待解决的问题,并对该领域的发展提出自己的观点.     

烧结金刚石串珠绳锯切花岗石的锯切力研究

本文对烧结金刚石串珠绳在锯切花岗石过程中，锯切力及锯切后工件表面的轮廓进行了跟踪检测，研究了锯切过程中，锯切力随锯切参数的变化，以及锯切力与工件表面轮廓的相互关系。实验结果表明：锯切过程中，工件上所承受的锯切力Fh和Fv随着线速度Vs的提高而减低，随着进给速度吩的提高而增加。垂直力与水平力之间存在着良好的对应关系，垂直力与水平力比约为4．18。加工后工件轮廓偏差量随着工件所承受的垂直力的增加而增加，两者之间呈指数关系。     

花岗石锯切过程中的锯切力特征

本文通过测量和分析锯切花岗石过程中锯切力以及锯切功率，对锯片所受的单位宽度法向力Fn‘和切向力Ft‘以及单颗金刚石磨粒所平均承受的法向力和切向力进行了研究，实验过程中在保持金刚石节块表面状态基本不变的情况下，对锯切深度ap，进给速度vf和锯片圆周线速度Vs进行了较大范围的变化，另外还对锯片磨损过程中锯切力的变化进行了跟踪测量。     

金刚石绳锯加工弧区锯切力分布的研究

本文针对金刚石绳锯的柔性加工以及长锯切弧区的加工特点,采用弧区内分段的实验方法,在弧区七个位置选取了50 mm的微段,对每个微段进行锯切力的测量,进而总结出锯切加工弧区内锯切力的分布情况.研究结果表明:当线速度和进给速度较小时,整个弧区的锯切力的波动较小,随着线速度和进给速度的增大,弧区锯切力在整个弧区的波动随之变大;...     

基于声发射技术金刚石组合圆锯片干切混凝土的切削状态研究

通过自行设计的多孔与非等弧长节块组合金刚石锯片与普通锯片的对比分析,揭示组合结构金刚石锯片的切削特征.通过分析金刚石圆锯片在锯切过程中混凝土声发射信号和锯切力信号特征,得出切削速度、进给速度、切削深度对AErms峰值平均值和Z轴锯切力的影响.结论表明声发射信号的变化规律与锯切力信号的变化规律有较好的一致性.其它切削条件不变,随着切削速度的增加,声发射均方根值和切削力平均值都减小;随着进给速度、切削深度的增加,声发射均方根值和切削力平均值都增大.且自行设计的组合锯片整体性能优于普通锯片.     

焊接吊耳锯切质量评定指标及影响因素

焊接吊耳是钢结构制造过程中用于吊装的重要零件。结合传统的锯切原理,从结构上分析焊接吊耳的锯切,为减小留根量,在利用带锯条锯切焊接吊耳时需要采用水平锯切方式,同时不能使用传统的带锯条扭转装置,而应该增大张紧力保证锯切质量。并将切口表面粗糙度Ra和留根斜度的正切值ρ作为锯切焊接吊耳质量的评定指标。采用正交实验法研究张紧力、锯切速度以及进给速度对焊接吊耳锯切质量的影响。研究表明:张紧力和进给速度对Ra和ρ的影响最大,锯切速度对粗糙度影响较小;张紧力越大,进给速度越小,则锯切质量越好。     

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.     

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.     

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。     

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.