GRAIN SHAPE EFFECT IN SUPERPLASTIC DEFORMATION

The method controlling grain shape in TMT processing and the effect of grain shape on char-acteristic parameters in superplastic deformation were discussed.The accommodation velocityof grahl boundary sliding,which is the dominant mechanism in superplastic deformation,andthe contribution of each mechanism to the total strain,as influenced by grain shape,were ana-lyzed.Grain shape has been shown to be an essential structural factor for superplasticity.Thenan analysis was made about the effect of grain shape on the region transition strain rate sothat a new concept,critical aspect for superplasticity,was worked out.These predictions werecompared with the measured results in an Al-Zn-Mg alloy.     

Al-Ti-B-RE细化剂对铝晶粒细化效果初探

对新型细化剂Al-Ti-B-RE的细化效果进行了探讨。结果表明：该中间合金是一种高效、长效的晶粒细化剂，当加入量为0．04％～0．10％，铝熔体在800℃静置30min的细化效果最显著，其效果优于进口Al-Ti-B细化剂。     

焊接热影响区微观结构演化的蒙特卡罗计算机模拟方法

焊接热影响区是影响焊接性能的主要区域。焊接热影响区的晶粒长大常常导致焊接热影响区成为性能薄弱的环节，对焊接热影响区晶粒长大的研究一直是焊接接头的重要研究课题。焊接热影响区微观结构演化与诸多因素密切相关，是一个复杂的过程。运用适当的计算机方法进行模拟，完成对晶粒生长的完全预测，具有重要的意义，可以为优化焊接工艺参数，提高焊接质量提供依据。在此对在模拟焊接热影响区微观结构的演化时采用的基本方法进行综述。     

Mn-Nb-Mo系X70级管线钢奥氏体再结晶规律的研究

研究了Mn-Nb-Mo系XT0级管线钢的再结晶规律，分析了变形温度、变形量等工艺参数对变形奥氏体再结晶百分数的影响，为现场控轧工艺的制定提供了理论依据。     

基于截面特征相容的曲面约束重构

为了从点云中重建高品质的曲面模型,提出一种基于截面特征相容的曲面重构方法.该方法将由点云切片获取的截面曲线分层次表达为直线、圆弧、B样条等基本曲线元和特征点的集合,并基于曲线微分几何属性,建立截面曲线特征点对应的数学模型,采用动态规划法求解并确定其初始对应关系,以曲线元特征匹配准则优化对应,逐步确立截面曲线间的特征对应关系,将特征对应关系映射为参数对应即可利用成熟算法逼近生成蒙皮曲面.实例表明,该算法获取的曲面模型不但满足精度和光顺性要求,而且忠实地反映了原始物理样件所蕴含的特征信息.     

Lipofilling in Breast Oncological Surgery: A Safe Opportunity or Risk for Cancer Recurrence?

Lipofilling (LF) is a largely employed technique in reconstructive and esthetic breast surgery. Over the years, it has demonstrated to be extremely useful for treatment of soft tissue defects after demolitive or conservative breast cancer surgery and different procedures have been developed to improve the survival of transplanted fat graft. The regenerative potential of LF is attributed to the multipotent stem cells found in large quantity in adipose tissue. However, a growing body of pre-clinical evidence shows that adipocytes and adipose-derived stromal cells may have pro-tumorigenic potential. Despite no clear indication from clinical studies has demonstrated an increased risk of cancer recurrence upon LF, these observations challenge the oncologic safety of the procedure. This review aims to provide an updated overview of both the clinical and the pre-clinical indications to the suitability and safety of LF in breast oncological surgery. Cellular and molecular players in the crosstalk between adipose tissue and cancer are described, and heterogeneous contradictory results are discussed, highlighting that important issues still remain to be solved to get a clear understanding of LF safety in breast cancer patients.     

Numerical simulation of microstructure formation ofAZ91 using mCA method

A stochastic model for simulating the microstructure formation of Mg alloy AZ91 during solidification was developed based on the finite element method（FEM） for macroscopic model of heat transfer calculation and a modified Cellular Automaton （mCA） for microscopic modeling of nucleation, growth of crystal. In this model, the effect of solute redistribution, interface curvature and preferred orientation was considered. A numerical simulation was developed with C＋＋ program language. The computation was carded out to understand the effect of varying processing parameters, such as nucleation parameters and heat transfer coefficient, on the microstructure formation of AZ91. The result of simulation was displayed on screen.     

反求工程的产品几何建模技术研究

分析了目前在反求工程产品几何建模中广泛应用的曲面模型的局限性，指出反求工程为实现创新功能必须采用产品特征模型，提出了基于实体造型的特征建模方法。这种方法可以避免曲面模型的缺陷，拓宽反求工程的应用范围，是实现三维重构的新方法。探讨了有关的理论和关键技术。     

电、磁场对金属凝固组织的影响及应用

利用外加物理场凝固细晶技术是目前材料加工领域的研究热点。综述了各种电、磁场对金属凝固组织的影响，并对其主要的机理进行了探讨；并对电、磁场在金属凝固成形中的应用和进一步研究进行了展望。     

Mn,Zr对Mg-Gd-Y合金组织与力学性能的影响

研究了微量Mn、Zr对Mg-13%Gd和Mg-9%Gd-4%Y合金铸态和挤压后的微观组织及力学性能的影响.结果表明:在铸态,含Zr合金的晶粒明显小于不含Zr的合金,而Mn对合金的铸态显微组织影响不大;将Mg-9%Gd-4%Y-0.6%Mn和Mg-9%Gd-4%Y-0.6%Zr合金挤压后,都可以得到非常细小均匀的等轴晶,晶粒尺寸约14 μm;这两个合金在挤压时效态(T5)的力学性能都明显优于WE54合金的,且Mg-9%Gd-4%Y-0.6%Zr合金比Mg-9%Gd-4%Y-0.6%Mn合金性能更好.