行李箱外板浮动整形模设计

介绍了某轿车行李箱外板的翻边侧整形模设计过程,行李箱外板的侧法兰翻边上存在凹包,其翻边方向和凹包成形方向不同,常规需要2道工序分别完成翻边和凹包成形。该模具突破了传统的设计结构,在翻边机构中设置了凹包成形机构,将2个不同方向的成形复合到1道工序中,减少了模具数量,降低了冲压成本和工装成本。     

Spinal Excitatory Dynorphinergic Interneurons Contribute to Burn Injury-Induced Nociception Mediated by Phosphorylated Histone 3 at Serine 10 in Rodents

The phosphorylation of serine 10 in histone 3 (p-S10H3) has recently been demonstrated to participate in spinal nociceptive processing. However, superficial dorsal horn (SDH) neurons involved in p-S10H3-mediated nociception have not been fully characterized. In the present work, we combined immunohistochemistry, in situ hybridization with the retrograde labeling of projection neurons to reveal the subset of dorsal horn neurons presenting an elevated level of p-S10H3 in response to noxious heat (60 °C), causing burn injury. Projection neurons only represented a small percentage (5%) of p-S10H3-positive cells, while the greater part of them belonged to excitatory SDH interneurons. The combined immunolabeling of p-S10H3 with markers of already established interneuronal classes of the SDH revealed that the largest subset of neurons with burn injury-induced p-S10H3 expression was dynorphin immunopositive in mice. Furthermore, the majority of p-S10H3-expressing dynorphinergic neurons proved to be excitatory, as they lacked Pax-2 and showed Lmx1b-immunopositivity. Thus, we showed that neurochemically heterogeneous SDH neurons exhibit the upregulation of p-S10H3 shortly after noxious heat-induced burn injury and consequential tissue damage, and that a dedicated subset of excitatory dynorphinergic neurons is likely a key player in the development of central sensitization via the p-S10H3 mediated pathway.     

磁流变动压复合抛光基本原理及力学特性

目的探究磁流变动压复合抛光基本原理及抛光力学特性。方法通过建立磁流变动压复合抛光过程中流体动压数学模型,分析抛光盘面结构化单元对抛光力学特性的影响规律,并优化其结构。搭建磁流变动压复合抛光测力系统,探究工作间隙、抛光盘转速、工件盘转速和凸轮转速对抛光力的影响规律,基于正交试验,优化抛光效果。结果抛光盘面结构化单元的楔形区利于流体动压效应的产生,且流体动压随楔形角和工作间隙的增大而减少,随楔形区宽度的增大而增大。结构化单元较为合理的几何参数为:楔形角3°~5°,工作间隙0.2~1.0 mm,楔形区宽度15~30 mm。法向力Fn随工作间隙的增大而减小,随工件盘转速的增大而增大,随抛光盘和凸轮转速的增大而先增大后减小;剪切力Ft随工作间隙的增大而减小,随工件盘、抛光盘和凸轮转速的增大均呈现先增大后减小的规律。通过正交试验获得优化工艺参数为:抛光盘转速60 r/min,工件盘转速600 r/min,凸轮转速150 r/min。在羰基铁粉(粒径3μm、质量分数35%)、SiC磨料(粒径3μm、质量分数5%)、工作间隙0.4 mm和磁感应强度0.1 T工况下,抛光2 in单晶硅基片4 h后,表面粗糙度Ra由20.11 nm降至2.36 nm,材料去除率为5.1 mg/h,初始大尺度纹理被显著去除。结论磁流变动压复合抛光通过在抛光盘面增设结构化单元,以引入流体动压效应,强化了抛光力学特性,并利用径向往复运动的动态磁场实现柔性抛光头的更新和整形,最终达到了提高抛光效率和质量的目的。     

撞楔在高岭土矿过流砂层中的应用

通过工程实例,阐述了使用撞楔作超前支护在非煤行业井巷施工中过流砂层中的成功应用。并且证明了使用撞楔作超前支护过流砂层等松软岩层的可行性。     

弹性流体动力润滑中的粘度楔理论

经典的弹性流体动力润滑 (弹流 )理论体系已经较完善的建立 .然而在实验和理论研究中 ,一些同经典的弹流理论相悖的现象被证实 ,使非经典弹流粘度楔理论的建立成为必然 .介绍了粘度楔理论建立的学术背景 ,综述了国内外相关机构的研究成果 ,分析了当今粘度楔理论的几个研究要点     

考虑桩-土非线性共同作用的横向受荷桩分析模型

基于桩周土 (砂土及粘土 )的常规三轴压缩试验 ,提出了一种有效计算水平横向受荷桩荷载与变形非线性关系的应力 -应变锥楔模型 (SSCW)法。该法从桩 -土系统共同作用机理出发 ,充分考虑了桩 -土间相互作用属性的变化对p -y曲线分析结果的影响。计算表明 ,通过SSCW法得到的桩土反应数值与实测值有良好的一致性     

深基坑工程土压力计算方法研究

在工程实践和有关文献的基础上 ,探讨了土压力计算公式及其分布模式的普遍形式及其与支护方式的关系 ,提出了用于确定岩土工程参数的滑裂面调查法。方法从极限平衡的概念出发 ,运用工程类比的思维方式 ,通过调查滑裂面几何参数临界深度z0 和滑裂面倾角θ来反演土体抗剪强度c,φ值     

岩石隧道全断面开挖技术

对隧道施工全断面开挖的各种钻爆方式、掏槽方式、爆破参数、合理布置炮眼等进行了综合分析,给出了实用的施工数据。采用楔形掏槽与台架相配合,形成了大楔形掏槽台架开挖模式,使施工进度及经济价值都有明显的提高。     

基于改进应变楔模型的固体-散体串联组合桩鼓胀变形及沉降分析

针对传统碎石桩易在桩顶1~3倍桩径的深度范围内发生鼓胀破坏的现象,首先,在现有工艺的基础上提出一种固体（混凝土）-散体（碎石散体材料）串联组合桩,并简要阐述其承载特性、施工工艺及破坏模式;其次,建立了串联组合桩鼓胀变形的计算模型,探讨串联组合桩的鼓胀变形机理;然后,对应变楔模型进行修正,并结合广义胡克定律,计算固体-散体串联组合桩的鼓胀变形值及桩身沉降值;最后,通过传统碎石桩及筋箍碎石桩鼓胀变形及沉降试验验证所提理论方法的合理性,结果表明：理论计算值与试验结果吻合较好,可为碎石桩复合地基设计提供一定的参考,具有理论及工程应用价值。     

Precast Concrete Blocks for High-Velocity Flow Applications

Precast concrete blocks can be used as erosion protection to a surface subjected to high-velocity water, for example a dam spillway.
The paper describes model testing carried out on flat and wedge-shaped blocks in a purpose-designed facility at the University of Salford, where an open channel discharge intensity of 0.5 m²/s can be accelerated to a velocity of 7.5 m/s.
The failure modes of tied and untied flat concrete blocks have been investigated under different laying and bedding conditions. The model results are compared to the findings from prototype studies. Results from experiments on wedge-shaped blocks of a Soviet design are also presented and confirm the Russian experience that the wedge shape is inherently stable at large discharges, a block of 100-m thickness being stable under a discharge intensity of 20 m²/s.