Research on voids deformation welding condition for manufacturing of heavy forgings

Crushing and diffusion welding are two critical healing stages of interior void defects in heavy forgings. The healing result depends on many factors during the forging process, such as stress, temperature, deformation and type of material, while the void diffusion welding condition is still not well known at the present. This paper is concerned with the deformation welding condition of the closed void interface in heavy ingot during the hot forging process. A void crushing experiment is carried out to recognize the microstructure of the closed void interface. According to the healing mechanism at high temperature, a new physical simulation model is setup to study the deformation welding process of the closed void interface based on the theory of atom diffusion and the interface contact mechanics prototype. Compared with the experimental results, the influence of deformation degree, forming temperature and holding time on the welding quality is discussed, and then the deformation welding condition of closed void interface is presented. The proposed condition helps to improve forging technology and product quality.     

长江口北槽悬沙垂线分布经验公式研究*

利用Rouse公式对长江口多次实测资料进行整理分析,得出了长江口北槽纵向悬沙垂线分布的特征,验证了描 述悬浮泥沙垂线分布的Rouse公式的适用性,阐明了利用Rouse公式推算得到的不平衡条件下泥沙沉速与实际泥沙沉速的差 异,并利用不平衡条件下的垂线分布公式和北槽悬沙垂线分布实测资料,率定和验证了不平衡输沙系数和垂线平均含沙量 的经验关系式,在此基础上,建立了适用描述长江口北槽悬沙垂线分布的经验公式,并通过实测资料得到了验证。     

奥运礼赞之旅BMW535iTOUnng漫游瑞士

从“老家”出发 在2004年希腊、2008年北京两届奥林匹克运动会之后,我们终于要等到2012年伦敦奥运会了,这是奥运会在离开欧洲8年之后也将再次回归,大家又要熬夜看比赛了。既然如此,为何不在能力和时间允许的条件下到现场去观赛呢？     

基于卓越工程师培养标准模式下的机械类专业实验室建设研究

为满足卓越工程师培养标准模式下机械类应用型工程师培养需求,针对机械类应用型人才培养的特点,分析实验室建设原则和实验室规划,提出适合卓越工程师培养标准模式的机械类应用型工程师培养的实验室规划与方案.     

高速客运专线轨道梁徐变变形研究进展

由于混凝土徐变的影响,高速客运专线轨道梁在长期荷载的作用下,变形随着时间不断增加,严重影响了轨道梁的使用性能,甚至危及行车安全：介绍了国内外有关混凝土徐变机理与特性的研究进展。在此基础上,对高速客运专线轨道梁徐变分析计算方法及控制措施方面的研究成果及工程经验进行了较为系统地总结;对将来高速客运专线轨道梁徐变的研究方向进行了展望。     

Poly(Dimethylbenzimidazolium) Iodide Assisted Dispersion of Multiwalled Carbon Nanotubes and Their Palladium Nanoparticle Hybrid

Experimental measurements of stresses and strains for lower extremity injuries (LEI) are invasive, and therefore, predictions require physiologically accurate 3D finite element (FE) models of the foot and ankle. In previous models, skin is typically neglected. However, experimental studies have shown that skin is much stiffer than soft tissue. In this study, the material sensitivity of skin on foot arch deformation is investigated. A finite element model of the foot is developed, incorporating bones, soft tissue, ligament, articulating surfaces, plantar aponeurosis, skin and plantar plate. Balanced standing is simulated without skin or with three different skin mechanical properties. By including different skin models, the foot static vertical stiffness, navicular displacement and plantar aponeurosis strain change significantly, when compared with the model without skin. The study shows that skin, showing a much stiffer behaviour than soft tissue, should not be neglected in the foot modelling. Further, the plantar plate considered in this model can give merit to modelling injuries such as plantar plate tearing.     

浅析市场营销的案例教学

在市场营销课教学过程中,学生中普遍存在的对一些基本理论和概念难以理解,难以掌握,以至兴趣缺乏的问题。案例教学可以较好的把理论和实践结合起来,让理论由于回归生活而变得更加丰满和富有魅力,从而激发学生的学习积极性,充分发挥其潜能,提高其分析问题,解决问题的能力。     

含粒料的半刚性基层材料最大干密度与最佳含水量快速测定法

确定材料的最大干密度与最佳含水量的常规方法是把此类材料按重型击实标准方法求得。当粒料含量在50％以下,所得结果正确,但此方法费工费时,且当粒料含量大干50％时,常规测得结果就有误。本文为解决此矛盾,提出了含粒料半刚性基层材料最大干密度与最佳含水量快速确定法,并例举测定结果,证明与实测值基本一致。灰土结碎(砾)石和石灰粉煤灰结碎(砾)石类,混合料的最大干密度只需按式Υ_0=V_1·Υ_1+V_2·ρ计算即可,最佳含水量W_0=W_1·A+W_2(1一A);对水泥结     

珠海市白蕉路一号桥加固设计

介绍了珠海市白蕉路一号桥桥台的加固设计.通过对桥台破坏原因的分析以及两个加固方案的综合比较,确定了最优方案;并对实施方案的几个细部构造设计作了重点说明.     

京沪高速铁路淮河特大桥96m系杆拱动力性能试验研究

系杆拱桥是一种集拱与梁的优点于一身的桥型,它将拱与梁两种基本结构形式组合在一起,共同承受荷载。为评估京沪高速铁路淮河特大桥96 m系杆拱的动力性能,检验列车通过时的平稳性,对96 m系杆拱的自振特性和动车组以各种速度通过桥梁时的动力响应进行测试。试验数据表明,该结构形式具有足够的竖向和横向刚度,动力性能良好,能够满足动车组最高350 km/h运行平稳性要求。