Martensitic stabilization and defects induced by deformation in TiNi shape memory alloys

Martensitic stabilization caused by deformation in a TiNi shape memory alloy was studied.Special attention was paid to the deformed microstructures to identify the cause of martensitic stabilization.Martensitic stabilization was demonstrated by differential scanning calorimetry for the tensioned TiNi shape memory alloy.Transmission electron microscopy revealed that antiphase boundaries were formed because of the fourfold dissociation of[110]B19'super lattice dislocations and were preserved after reverse transformation due to the lattice correspondence.Martensitic stabilization was attributed to dislocations induced by deformation,which reduced the ordering degree of the microstructure,spoiled the reverse path from martensite to parent phase compared with thermoelastic transformation,and imposed resistance on phase transformation through the stress field.     

中厚钢板板形控制技术综述

本文综述了中厚钢板板形控制内容,纵向板形控制,横向板形控制,平面板形控制以及板形检测技术,并对其技术提出今后的展望。     

单试样三点柔度法测金属材料JR曲线及其条件起裂值

在单试样卸载柔度法及单试样三曲线法基础上,提出了一种更简便的测定金属材料ＪＲ曲线及其条件起裂值的单试样三点预先度法,并用该方法测定了１Ｃｒ１／２Ｍｏ钢、１６ＭｎＲ风和ＷＣＦ６２钢的ＪＲ曲线及其条件起裂值,与标准的多试样法相比,误差均在工程许可范围内。     

损失气求取方法研究

当逸散时间较长时，用直线回归法采取损失气结果偏低，而逸散时间较短取点数少时，结果偏高。曲线拟合法是比较实用的一种方法，但计算工作量较大。经过模拟实验证明，在变围压条件下，甲烷的解吸规律也服从经验方程Ｑ＝ＷＪ［１－ｅｘｐ（１－ｍ＿１￣ｍ２／ｍ＿２］，并推导出迭代法求取损失量的计算公式。     

Matching and Interpolation of Shapes using Unions of Circles

While the notion of shape of an object is very intuitive, its precise definition is very elusive, and defining a useful metric for the shape distance between objects is a difficult endeavor. At the same time many successful techniques have been developed which interpolate between two objects, so in essence interpolate between shapes. W e present here work which uses a representation of objects as union of circles to define a distance between two objects and to base a method to interpolate between the two. This method can be used in a totally automatic fashion (that is, without any user intervention), or users can guide a pre-registration phase as well as a segmentation phase, after which the matched segments are interpolated pair-wise. The union of circles representation of the two objects is obtained from the Delaunay triangulation of their boundary points. The circles can be simplified to obtain smaller data sets. The circles are then optimally matched according to a distance metric between circles which is a function of their position, size, and feature, that is, a local configuration of circles. The interpolation between the two objects is then obtained by interpolating between the matched pairs of circles (the interpolations can be affine or non -affine). Examples with simple and more complex objects show how the technique can give results which correspond closely to the human notion of shape interpolation. The interpolations shown include some between a calf and a cow and between a cow and a giraffe. The examples given are in two dimensions, but all the steps except the segmentation have been implemented as well for three dimensional objects. W e also show the results of computation of distances between the objects used in our examples.     

带孔等厚薄壳荷重传感器弹性元件的形状优化

建立带孔等厚薄壳荷重传感器弹性元件的优化参数模型、有限单元计算模型及优化数学模型,确定电阻应变计的粘贴位置,用结构分析软件ANSYS5.7及一阶优化方法优化弹性元件的形状,提高弹性元件在贴片位置的应变响应。     

一种新型设备用断路器——NDB3的结构原理及应用

介绍了液压-电磁式设备用断路器的工作原理、产品特点及其在典型行业中的应用,阐述了这一区别于传统热磁式断路器的优点,及在通信行业中的典型应用。     

Epigenetic and Genetic Factors Related to Curve Progression in Adolescent Idiopathic Scoliosis: A Systematic Scoping Review of the Current Literature

Adolescent idiopathic scoliosis (AIS) is a progressive deformity of the spine. Scoliotic curves progress until skeletal maturity leading, in rare cases, to a severe deformity. While the Cobb angle is a straightforward tool in initial curve magnitude measurement, assessing the risk of curve progression at the time of diagnosis may be more challenging. Epigenetic and genetic markers are potential prognostic tools to predict curve progression. The aim of this study is to review the available literature regarding the epigenetic and genetic factors associated with the risk of AIS curve progression. This review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out in January 2022. Only peer-reviewed articles were considered for inclusion. Forty studies were included; fifteen genes were reported as having SNPs with significant association with progressive AIS, but none showed sufficient power to sustain clinical applications. In contrast, nine studies reporting epigenetic modifications showed promising results in terms of reliable markers. Prognostic testing for AIS has the potential to significantly modify disease management. Most recent evidence suggests epigenetics as a more promising field for the identification of factors associated with AIS progression, offering a rationale for further investigation in this field.     

基于有限元分析的板料形状对S梁拉深的影响

基于DYNAFORM动力显式有限元分析软件,将数值模拟技术应用于S梁的坯料优化过程,研究了不同的毛坯形状、尺寸对S梁拉深的成形极限图、厚度分布、减薄率的影响。通过对比分析不同的坯料成形模拟结果,确定较为合理的毛坯形状尺寸。研究结果表明:方式1是不可取的,而方式2能很好地成形出合格零件,最大减薄率为16.6%,最大增厚率为1.84%。在法兰处可以适当添加拉延筋以缓解起皱趋势。     

DX挤扩灌注桩在某高层建筑中的应用实例

孝感天紫国际大酒店,主楼21层,附楼5层,总用地面积6732m^2。总建筑面积3．9万m^2,地下室一层,基础采用小直径DX桩,为业主节约了投资,取得了较好的技术经济效益。