一维精密转动定位平台的分析与设计

基于柔顺机构设计了一种新型的一维精密转动定位平台.首先建立了平台的数学分析模型,在此基础上,通过优化设计得到了平台的最优尺寸.利用有限元软件验证了理论建模和优化结果的正确性.制造了原型样机,进行了实验研究,对平台进行了标定,并分析了平台的定位误差.     

动臂式塔式起重机变倍率装置的设计

简述了动臂QT900塔机的变倍率原理,根据变倍率要求设计两种方案.并分析其合理性和探讨对结构的影响.经过比较,第二种变倍率方案经过施工检验.获得了更好的效果.实现了变倍率的功能,并提高了整机性能.     

面向设计与制造的数字化工厂平台

分析了数字化工厂产生的背景及其内涵.基于数字化工厂协作平台的概念模型,构建了平台的体系结构.基于组件库的管理思想,设计了离散型制造企业模型资源库的开发流程.具体介绍了数字化工厂平台中各个模块的功能和实施流程.提出了数字化工厂平台建设中需解决的关键问题.     

混流生产车间布局研究

总结了车间布局的一般原则.提出了矩阵运算方法判断混流生产线上各工序的关系,并判断工序冲突的存在.提出了处理工序冲突的方法.定义了混流生产线的工序时间,节拍以及工作地时间.结合流水线平衡方法,得出了使混流生产线平衡的方法.根据混流生产的特殊性,提出了混流生产车间布局的方法.     

蠕动机器蛇的仿生设计和运动分析

通过对自然界中蛇的骨架结构和运动机理进行分析,提出了一种可以实现三维运动的机械结构.同时,在此基础上建立了机器蛇行波运动的运动学模型,规划了机器蛇的蠕动步态.并对理论步态进行了合理的近似.进而实现了机器蛇的蠕动前进.此外,通过试验证明了其机械结构和运动模型的可行性.     

分析规模超临界萃取装置限流器的改进设计

本文介绍了分析规模超临界萃取装置限流器的发展趋势,并详细介绍了一种新型限流器的设计.该限流器通过给阀体控温加热.彻底解决了超临界萃取中的冰堵问题.限流器采用两组阀结构,延长了限流器的使用寿命.     

基于Unigraphics的氧枪喷头快速成型技术研究

介绍了利用UG平台快速获得四孔氧枪喷头三维CAD模型,输出.STL文件到HR.P-Ⅱ系统中进行图形处理,并应用了分层实体制造工艺LOM方法进行快速成型加工.实现了氧枪喷头的快速数字化成型技术.经实践证明,提高了产品的精度,缩短了制造周期,并得以很好的应用.     

发挥土地流转政策导向作用推进先导区农机合作服务组织建设

望城,是"长株潭"两型社会建设先导区.农村土地承包经营权的流转,为农村农机合作服务组织建设.创造了一个更加宽阔的舞台.农机专业合作社按照"政府引导.市场运作"的方式组建,按照"依法自愿,有偿服务"的方式运行.为本地农业生产服务和开展跨区作业等方面,作出了一定的贡献.也积累了一定的经验.     

微型数控材料扭转试验机机械系统虚拟设计及仿真

设计了最大转矩为10 N·m的数控材料扭转试验机机械系统,阐述了机械系统加载原理,根据试验机的参数,对步进电机、减速器、联轴器等标准件进行了选择.同时,自主设计了试件夹具及导向支撑机构等零部件.在设计中应用计算机辅助设计软件SolidWorks对组成零件进行了实体建模、装配、有限元分析.以及运动仿真.并结合机械设计理论进行了零件的分析校核,以保证零件安全可靠.     

抽油机的发展及抽油模式的改进

简述了抽油机的发展历程,分析了各阶段抽油机的特点及存在的问题.同时结合现阶段油田生产的特点,分析了节能抽油机的发展趋势.从一个新的角度分析了抽油机节能改进的方向.提出了"一机双井"的工作模式,做了简单的定性分析.     

Molecular dynamics simulation of dislocation nucleation and motion at γ/γ′ interface in Ni-based superalloy

Molecular dynamics simulations are conducted on the dislocation behavior at the apices and edges of cuboidal Ni₃Al precipitate in a pure Ni matrix, or the idealized γ/γ′ microstructure in a Ni-based superalloy. A tensile simulation of the [001] direction is implemented with a periodic cell that has eight cubic precipitates in order to investigate the nucleation site of dislocation in the idealized microstructure with no defects other than the γ/γ′ interfaces. The effect of residual internal stresses on the stability of the interfaces is also discussed. Other simulations are conducted on the behavior of edge dislocations nucleated from a free surface and proceeding in the γ matrix toward γ′ precipitates under shear force. Dislocation pinning at γ′ precipitates, bowing-out in the γ channel, pile-up and nucleation of superdislocation in the γ′ precipitate are simulated and inspected in detail. Discussions on the size of the γ/γ′ microstructure and the sharpness of the edge of the γ′ precipitate are also presented.     

Effect of conformational changes and differences of proteins on frictional properties of poly(vinyl alcohol) hydrogel

In this study, albumin or γ-globulin, both of which are included in natural synovial fluid, was used as an additive into lubricants to investigate the ability to reduce the friction for poly(vinyl alcohol) hydrogel in mixed lubrication. It was found from a measurement in circular dichroism that albumin contains a large amount of α-helix structure and γ-globulin contains a large amount of β-sheet structure. The lubricant containing only albumin showed low friction compared to the lubricant containing only γ-globulin. The effect of protein boundary film was clarified by changing lubricant. Albumin kept the friction low after changing from γ-globulin used at initial rubbing, but γ-globulin increased the friction after changing from albumin at initial rubbing. From a sliding distance of 600 m, albumin showed lower friction but γ-globulin showed higher friction. Therefore, in the case of friction decreasing, γ-globulin forms a tight adsorbed layer and subsequently albumin forms a layer with low shearing strength. Hence, it is important to apply the adsorption layer of γ-globulin at the bottom and make a layered structure composed of albumin and γ-globulin to reduce both friction and wear.     

3(3-RPS)并-串联机构及其运动学分析研究

针对并联机构运动学和动力学性能方面存在的问题,提出了一种新结构-3(3-RPS)并-串联机构,对3(3-RPS)并-串联机构进行了运动学方面的研究,对3(3-RPS)并-串联机构的结构特点进行了介绍,利用螺旋理论及修正的Kutzbach–Grüble公式对3(3-RPS)并-串联机构进行了自由度计算,利用机构影响系数法和螺旋理论对3(3-RPS)并-串联机构的速度和加速度进行了建模,得到了3(3-RPS)并-串联机构速度和加速度的理论模型,利用工程分析软件ADAMS和Abaqus对3(3-RPS)并-串联机构进行了运动学仿真及结构受力分析,得到了上平台在空间中的速度和加速度曲线变化图与机构的结构受力变形图。研究结果表明:3(3-RPS)并-串联机构的自由度数为9,速度和加速度值等于各层之和;本研究分析3(3-RPS)并-串联机构运动学的方法也适合其他并-串联机构。     

A simple approach to estimate failure surface of polymer and aluminum foams under multiaxial loads

From mechanical point of view, it is required to have a criterion for evaluating the failure of cellular solids (foams) under multiaxial loads. Well-documented experimental results in the literature show foams could fail by several mechanisms, e.g., elastic buckling, plastic yielding, brittle crushing or brittle fracture. In the previous years, both theoretical and phenomenological approaches have been applied to obtain the failure surface of various foams. The purpose of this paper is to present a simple approach to estimate the complete failure surface of “non-textured” foams. The predicted results of polymer and aluminum foams are compared with the experimental results reported in the literature. It is found that three selected tests will be sufficient to estimate the complete failure surface of a foam. The recommended testing stress states are σ₁=σ₂=σ₃>0, σ₁=σ₂=σ₃<0, and σ₁=−σ₂=−σ₃ (or σ₁=−σ₂, σ₃=0).     

基于 SolidWorks的 CAPP系统的可视化装配决策

在SolidWorks三维设计软件的平台上,通过对三维装配工艺顺序规划决策技术、三维装配工艺路径规划决策技术、三维装配干涉检查技术、三维装配过程的几何推理技术、三维装配过程优化方法决策技术以及三维可视化装配仿真技术的分析和研究,从而为基于SolidWorks的可视化装配CAPP系统的开发提供技术基础。     

miRNA-148b-3p targeting SOCS3 inhibits macrophage M2 polarization by JAK2/STAT3 pathway in immune thrombocytopenia

Aberrant expression of miRNAs is significantly correlated with the occurrence of immune thrombocytopenic purpura (ITP). The immune imbalance of M1/M2 macrophage contributes to the development of ITP. However, the role of miR-148b-3p in macrophage phenotype imbalance remains unknown in ITP. In this study, we aimed to explore whether miR-148b-3p inhibits M2 macrophage polarization in ITP and to investigate the underlying mechanism. Peripheral blood from 22 ITP patients were collected, and real-time PCR confirmed that miR-148b-3p was up-regulated and Western blot analyses detected the expression of SOCS3 was down-regulated. Subsequent dual-luciferase reporter gene assay indicated that miR-148b-3p could bind to SOCS3. Furthermore, we found significant correlation between miR-148b-3p expression and platelet count. Applying gain and lose the function experiments of miR-148b-3p and SOCS3, we demonstrated that suppression of miR-148b-3p or up-regulation of SOCS3 promoted macrophage M2 polarization by inhibiting JAK2/STAT3 pathway. Together, our findings demonstrate that that miR-148b-3p targeting SOCS3 inhibits M2 macrophage polarization via JAK2/STAT3 signaling in ITP.     

利用综合热分析仪研究纳米二氧化钛凝胶的热稳定性

以TiCl4为原料,分别以Cr(NO3)3、Fe(NO3)3和Al(NO3)3为掺杂剂,采用共沉淀制备了含不同掺杂剂和掺杂量的纳米二氧化钛凝胶,利用综合热分析仪(热重分析一差示扫描量热联用仪,简称DSC-TG)研究了纳米二氧化钛凝胶从30-1100℃热稳定性以及组分和物相的变化,XRD测定了二氧化钛凝胶在煅烧过程中晶型转变。结果表明:含不同掺杂剂和不同掺杂量凝胶的DSC-TG曲线有很大的差别;Cr3+和Fe3+掺杂能促进金红石相的形成,Al3+掺杂有利于锐钛矿相的稳定。     

X3D基于Java的开发工具和浏览器--Xj3D的浅析

本文对基于WEB的交互式三维图形规范X3D（Extensible 3D,可扩展3D）与Java 3D技术的结合Xj3D工具进行了研究,详细阐述了该工具包的结构,各主要组成组件的功能与作用以及各组件之间的相互关系,并给出了Java 3D装载组件装载文件的一种具体实现方法.     

Utilizing a simple and reliable method to investigate the optical functions of small molecular organic films - Alq3 and Gaq3 as examples

This work reports on the optical functions of tris(8-hydroxyquinolinate) gallium and aluminum small molecular organic films grown by utilizing a home-made thermal evaporator and studied with a spectrophotometer. The non-dispersive refractive index of the Gaq3 and Alq3 films was calculated as 1.77 and 1.68, respectively. The higher refractive index of Gaq3 was attributed to the higher molecular packing density of Gaq3 compared to that of Alq3. A larger dielectric constant for Gaq3 was noticed, indicating the presence of a higher density of states and space charge accumulation in the Gaq3 films compared to those of Alq3. We assigned the presence of direct allowed transition to energy gaps of 2.80 eV and 2.86 eV for the Gaq3 and Alq3 films, respectively. These differences are thought to be caused by the effects of central metal cations of Ga³⁺ and Al³⁺ on their molecular quinolinate ligands.     

陶瓷与灰铸铁配副在水润滑下的摩擦学性能

比较了在蒸馏水润滑下Si3N4、Al2O3陶瓷与灰铸铁副的摩擦学性能,结果表明：Al2O3陶瓷的磨损体积远小于Si3N4,但与Si3N4配副时灰铸铁的磨损体积明显小于与Al2O3配副时的磨损体积。其摩擦系数也较小（0.02)。用SEM观察发现Al2O3陶瓷磨擦表面粗糙,有少量的转移膜形成;而Si3N4磨擦表面光滑,与其对应的灰铸铁磨面上存在含石墨的润滑膜。