AFAM 7050铝合金的数值模拟

AFAM是一种新型的增材制造技术,它将传统的搅拌摩擦焊拓展到增材制造领域。本文探索了基于ANSYS平台的AFAM温度场和残余应力的模拟。基于完全热力耦合模型,对AFAM进行数值模拟。选取旋转速度为750r/min,前进速度为60 mm/min,对温度场进行计算,并对最终状态下的残余应力进行分析对比。结果表明:AFAM的加工温度区间在固相线附近,残余应力主要是纵向残余应力。

AFAM 7050铝合金的时效工艺研究

利用先进摩擦增材制造技术(AFAM)制备出7050铝合金试样,采用光学显微镜、扫描电镜、显微硬度测试仪的方法,研究了试样原始态与时效后的组织与硬度。结果表明,AFAM 7050铝合金由等轴、细小晶粒的再结晶区与其连接区两种形貌交替分布组成,再结晶晶粒平均尺寸大约为3-8μm;时效后晶粒发生了一定程度的长大,晶界出现了平直化现象,并析出了许多第二相,但依旧存在孔洞类缺陷和结合类缺陷;AFAM 7050铝合金厚度方向硬度存在梯度,上表层硬度最小,时效后硬度先增加后减小,最佳时效工艺为120℃/4h预处理+160℃/3h终时效。

6061铝合金先进摩擦增材制造(AFAM)复合强化机理控性试验的研究

本文以工业常用铝合金6061为例首次介绍了先进摩擦增材制造(AFAM)概念、复合强化机制和拉伸试验结果。结果数据表明:AFAM细晶工艺基础上的热处理强化加变形强化可以接近或超过传统母材性能,具有深入技术研究和工程应用价值。

低频低能量超声联合微泡对前列腺细胞的影响

目的:采用原子力声显微镜及透射电镜观察低频低能量超声联合微泡对前列腺癌细胞DU145及正常前列腺上皮细胞RWPE-1的作用。方法:两种细胞均分为对照组、单纯超声组、超声联合微泡组。对照组加入一定比例的生理盐水,不进行超声辐照;单纯超声组加入相同比例的生理盐水,用发射频率为21 k Hz的低频超声辐照,辐照2 min,占空比30%;超声联合微泡组加入同前相同比例的微泡造影剂悬浊液,用与单纯超声组相同的超声辐照。处理过的细胞立即用原子力声显微镜观察其形貌并计算其杨氏模量。同时,对同一处理方式的对照组及超声联合微泡组细胞继续培养24 h后,用透射电镜观察细胞。结果:单纯超声组的DU145细胞及RWPE-1细胞的细胞形态与对照组无明显变化;超声联合微泡组的DU145细胞及RWPE-1细胞形态呈类圆形,细胞表面可见放射状显微丝状结构,细胞膜表面可见多个大孔状结构;超声联合微泡组的DU145细胞的弹性模量较RWPE-1细胞大,且与对照组相比,两种细胞的弹性模量均变大,DU145细胞尤甚。透射电镜观察结果示对照组的两种细胞未见细胞自噬,而超声联合微泡组两种细胞都出现自噬现象,其中DU145细胞中可见凋亡现象。结论:低频低能量超声联合微泡可引起前列腺癌DU145细胞及正常前列腺上皮RWPE-1细胞的细胞膜出现孔状结构,并诱导其自噬,且对DU145细胞的损伤大于RWPE-1细胞。

Evaluating Local Elasticity of the Metal Nano-films Quantitatively Based on Referencing Approach of Atomic Force Acoustic Microscopy

Traditional technique such nanoindenter（NI） can＇t measure the local elastic modulus at nano-scale（lateral）. Atomic force acoustic microscopy （AFAM） is a dynamic method, which can quantitatively determine indentation modulus by measuring the contact resonance spectra for high order modes of the cantilever. But there are few reports on the effect of experimental factors, such length of cantilever, contact stiffness on measured value. For three different samples, including copper（Cu） film with 110 nm thickness, zinc（Zn） film of 90 nm thickness and glass slides, are prepared and tested, using referencing approach in which measurements are performed on the test and reference samples （it＇s elastic modulus is known）, and their contact resonance spectra are measured used the AFAM system experimentally. According to the vibration theory, from the lowest two contact resonance frequencies, the tip-sample contact stiffness is calculated, and then the values for the elastic properties of test sample, such as the indentation modulus, are determined. Using AFAM system, the measured indentation modulus of copper nano-film, zinc nano-film and glass slides are 113.53 GPa, 87.92 GPa and 57.04 GPa, which are agreement with literature values Mcu--105-130 GPa, Mzn = 88.44 GPa and Molass = 50-90 GPa. Furthermore, the sensitivity of contact resonance frequency to contact stiffness is analyzed theoretically. The results show that for the cantilevers with the length 160 pm, 225 μm and 520 μm respectively, when contact stiffness increases from 400 N/m to 600 N/m, the increments of first contact resonance frequency are 126 kHz, 93 kHz and 0.6 kHz, which show that the sensitivity of the contact resonance frequency to the contact stiffness reduces with the length of cantilever increasing. The novel method presented can characterize elastic modulus of near surface for nano-film and bulk material, and local elasticity of near surface can be evaluated by optimizing the experimental parameters using the AFAM system.

施维群辨治黄疸经验浅谈

[目的]探讨总结施维群教授辨治黄疸的学术思想与临证经验,以更好地传承与创新。[方法]通过跟随施维群教授临证抄方,整理相关病例资料,从病因病机、治法方药等方面阐述和总结施维群教授治疗黄疸病证的学术观点和临床经验,并附以验案举隅。[结果]施维群教授辨治黄疸思维独特,注重疾病本身的致病因素,辨证从脏腑、气血入手,认为黄疸病邪主要在于湿、瘀、热、火、虚,病位涉及肝、胆、脾、肾等脏腑。提出"治湿、治血、扶正"三大治则,以疏导湿热、运脾化浊,消瘀通络、疏肝清热,调治心脾、温补肾阳为主要治疗方法,临床取得较好疗效。所举医案,予以佐证。[结论]施老师治疗黄疸的学术思想和临床经验独到,其治法变通,用药灵活,在实践中行之有效,为临床治疗提供新的诊疗思路,值得深入学习与认真体会。