压接缺陷低辐射射线检测装置设计及功能验证

针对耐张线夹压接缺陷缺乏有效便捷检测手段的问题,开发了 一套轻量化、低辐射数字射线检测仪HNDR.为了实现HNDR的轻量化,设计了专用微型射线机;进行了射线机管套辐射屏蔽层、辐射防护腔以及操作侧外壳防护层三道递进式辐射防护设计,实现了 40cm范围内辐射剂量140nGy/h,远低于国标规定的公众豁免剂量,满足无防护操作...     

Crosslinking-mediated activation of the FcεRI: Does it need antigen for success?

Mast cells (MCs), hematopoietic cells of the myeloid lineage, are well-known for their pro-inflammatory nature contributing to the development of various allergic and autoimmune diseases. One of the characteristic receptors on MCs, the high-affinity receptor for IgE (FcεRI), is activated in its IgE-bound state via binding and crosslinking by polyvalent antigen. This results in its phosphorylation by the SRC family kinase LYN, initiating differential signaling pathways, eventually triggering immunological effector functions, such as degranulation and cytokine production. Few publications have reported on FcεRI-dependent but antigen-independent MC activation by antibody-mediated crosslinking of membrane molecules (e.g., transmembrane proteins and glycosphingolipids) that are both localized in membrane rafts and in close vicinity to the FcεRI. In this Viewpoint we will briefly introduce FcεRI-mediated MC stimulation, cite examples of FcεRI-proximal molecules, the crosslinking of which can cause FcεRI-dependent MC activation, and discuss the potential of certain viruses as well as auto-antibodies to act as indirect FcεRI-crosslinking agents. In latter cases, antigen-independent FcεRI-mediated pro-inflammatory MC activation could contribute to the development of detrimental cytokine storms.     

Large deformation compression–torsion behaviour of a titanium alloy and its modelling

A range of sequential and compound compression-torsion tests has been carried out on titanium alloy IMI834 at 1000°C and nominal true strain rate 5 × 10⁻³ s⁻¹, typical of forging conditions. The tests were used to investigate initial and subsequent yield and flow behaviour, the nature of the material hardening and the effect of flow softening on subsequent deformation. In addition, a material model with isotropic or directional hardening has been used to predict the material behaviour.The results show that the material behaviour at large strains is reasonably isotropic, although a directional hardening model provides slightly better quantitative agreement with the experimental results. Large pre-strains (0.4), either axial or torsional, are found not to change significantly subsequent material behaviour. A stress state dependence of flow softening is observed to exist.The material model presented is shown to give good quantitative agreement of predicted and experimental results.     

浅谈应变片靶式流量计的应用

由于靶式流量计在测量高粘度液体中具有独特的优点,因此在炼油化工领域得到了广泛的应用。本文详细阐述了靶式流量计的工作原理,对传统的和新型的靶式流量计特点及应用加以分析比较,同时通过调查研究生产过程中出现的典型故障,提出了解决问题的方法。     

基于等刚度条件的薄壁结构的一种材料替代轻量化设计分析方法

通过对板壳结构有限单元的弯曲应变能和膜应变能进行分析,得到一个采用不同材料的薄壁结构的刚度之间的近似解析关系式。将其与结构刚度的有限元计算分析过程相结合,提出一种不同材料但等刚度的薄壁结构的迭代设计方法和材料替代轻量化分析方法。分析得到的薄壁结构关于板壳的弯曲应变能占总的应变能的比例  的等刚度曲线,可用于直观地评价材料替代得到的等刚度结构的轻量化效果,可指导薄壁结构的轻量化设计。分析表明,材料替代对薄壁结构刚度的影响不仅与材料的弹性特性和板壳厚度相关,还与给定载荷下结构的  参数相关。对于铝板替代钢板的薄壁结构设计问题, 越高,则等刚度铝板结构的轻量化效果越明显。通过对一个悬臂薄壁钢板曲梁结构和一个典型车身接头结构的材料替代设计和轻量化分析,验证了提出的设计、分析方法的有效性和结论的正确性。     

吹扫-捕集技术在烟草行业中的应用研究进展

吹扫-捕集技术不用有机溶剂萃取和浓缩,减少了样品损失和对环境的污染,对挥发性有机物检测具有灵敏度高、检测限低、定量准确、操作简便等特点。本文综述了吹扫-捕集技术在烟草行业中对卷烟原材料、卷烟烟气、烟草行业工业污水、及烟草种植土壤检测等应用方面的研究,并对吹扫-捕集技术在烟草行业中的应用进行了展望。     

橡胶纯剪试件断裂力学分析

在橡胶材料纯剪试件中,当裂纹的长度和试件的高度尺寸接近时,应变能释放率与裂纹尺寸无关,由于存在这个特点,纯剪试件经常被用来研究橡胶材料的断裂属性。文中对橡胶纯剪试件在试件中心线上分别存在中心裂纹和边缘裂纹,以及粘接界面分别存在中心裂纹和边缘裂纹的情况进行非线性有限元分析,并将有限元计算的应变能释放率与已存在的解进行比较。对于长裂纹,有限元解与已存在的解吻合较好;但是对于小裂纹,有限元解与已存在的解之间仍然存在一些差异。     

合金化镀锌板的镀层脱落分析

跟踪拍摄合金化镀锌板双球冲成形时的镀层脱落过程,发现双球冲行程变化影响镀层脱落时间、部位与程度。结合自行开发的镀层自动评价系统分析镀层脱落程度,表明双球冲行程会影响镀层应变,镀层脱落程度与镀层应变有关。脱落主要发生在压应变区域,压应变越大,脱落程度越大。对各变形阶段应变进行有限元仿真,对比镀层的实际脱落过程,进一步发现压应变对镀层脱落的影响关系：只有压应变增大到某极限值,镀层才开始脱落;压应变继续增大,脱落继续且程度加大;压应变到达最大值之后再减小,脱落过程随即中止。     

液压胀形汽车桥壳的强度及疲劳寿命分析

在桥壳缩径工艺小批量生产试验基础上,对缩径管坯进行压缩实验,得到桥壳材料的硬化规律,揭示出第一次缩径强化占材料总强化的86.62%;经理论分析得到在桥壳材料强化1.78倍情况下,桥壳疲劳寿命提高96.91倍。以0.75 t载重车液压胀形桥壳为例,利用有限元分析软件ANSYS对其许用强度、静强度、疲劳强度(寿命)及其承载能力进行分析,得到液压胀形桥壳的强度变化规律:疲劳寿命相同时,其失效应力提高57.67%,疲劳寿命为国家标准80万次时,其承载能力提高33.33%。以上研究为液压胀形桥壳优化设计提供了可靠的参考。     

薄板等离子弧三维成形的工艺方法

平面薄板的等离子弧成形提出了一种有效实用的工艺方法.方法的重要特征是它首先计算成形一个特定形状所需要的应变场,利用应变场矢量和扫描路径方向垂直的关系设计扫描路径.等离子弧热参数通过应变场与等离子弧功率和扫描速度的关系确定.此方法在成形两种不同双曲形状上的有效性已经被仿真和试验所验证.