矿用对旋轴流式主通风机叶轮有限元分析

通过建立有限元分析模型,对叶轮的主要零部件进行应力、变形分析,据其结果考虑减少应力集中和强度裕量,改进叶轮结构.样机试验表明,叶轮质量减小了26%,降低了风机的噪声和振动,改善了配套电机轴承的受力状况,提高了使用寿命.该分析方法在同类产品中有应用的可能性.     

粗面岩储集层录井评价方法

辽河油田粗面岩油气藏比较发育，但储集层的均质性较差，增加了对其评价的难度。该文利用核磁共振技术和气相色谱技术在储集层评价上具有的独特技术优势，经过现场录井的不断实践，总结了粗面岩油气层的综合解释方法，建立了粗面岩储集层评价标准，并在实际中加以应用，取得了较好的效果，为辽河油田的进一步勘探和开发提供了可靠的依据。     

改善PCB镀铜均镀性

该文阐述了改善PCB镀铜均镀性的基本方法。     

MLD结构下电磁兼容混响室内场均匀性分析

为了进一步提高电磁兼容混响室内场均匀性,提出了最大长度散射体(MLD)一种新的位置,通过时域有限差分(FDTD)方法对混响室内的场进行了仿真分析,并与设置搅拌器情况下的混响室内场均匀性以及散射体位于混响室内6个面情况下混响室内的场均匀性作了比较。结果表明提出的散射体位置可有效地提高混响室内场均匀性。     

Post-yield response of cold-cambered wide flange steel beams

The post-yield response of steel beams is important in steel fabrication particularly for setting cambers. A commonly used cambering process known as “cold cambering” consists of bending the girder about its strong axis using single or dual symmetrically applied concentrated loads. This paper recasts available solutions for wide flange steel beams relating loads to permanent deformation in parametric form to determine the effect of cross-sectional geometry and load position on its post-yield response. Sensitivity analyses were then conducted to identify appropriate values of these key parameters and their impact on alternative cambering set-ups. This allows optimization of the cold cambering operation for single- and dual-load systems. The analysis shows that dual-load systems offer significant benefits over single-load systems as they develop the required camber profile at smaller loads without overstraining the steel section. The best results are obtained if the spacing between the two loads is kept within one-third to one-quarter of the span.     

A comparative study of the effect of Pd-doping on the structural,optical, and photocatalytic properties of sol–gel derived anatase TiO2 nanoparticles

Pd-doped anatase TiO₂ nanoparticles were synthesized by a modified sol–gel deposition technique. The synthetic strategy is applicable to other transition and post-transition metals to obtain phase-pure anatase titania nanoparticles. This is important in the sense that anatase titania forms the most hydroxyl radicals (compared to other polymorphs like rutile, brookite, etc.) for better photocatalytic performance. XRD and Raman data confirm the phase-pure anatase formation. Doping of Pd²⁺ into Ti⁴⁺ sites (for substitutional doping) or interstitial sites (for interstitial doping) creates strain within the nanoparticles and is reflected in the XRD peak broadening and Raman peak shifts. This is because of the ionic radii difference between Ti⁴⁺(∼68 pm) and Pd²⁺(∼86 pm). XPS data confirm the formation of high surface titanol groups at the nanoparticle surface and a large number of loosely bound Ti³⁺–O bonds, both of which considerably enhance the photocatalytic activity of the doped nanoparticles. A comparative study with other metal doping (Ga) shows that TiO₂: Pd nanoparticles have more Ti³⁺–O bonds, which enhance the charge transfer rate and hence improve the photocatalytic activity compared to other transition and post-transition metal-doped titania nanostructures.     

喹(噁)啉-2-羧酸标准物质的制备研究

建立了一种喹(噁)啉-2-羧酸(QCA)合成工艺路线,选择适当的方法对产品进行纯化,制备标准品候选物,并利用IR、UV、1 HNMR和MS技术对其进行定性鉴定.卡尔费休法和热重分析法分别用于水分和无机杂质的分析;建立优化了QCA主成分定值的高效液相色谱(HPLC)法,对含量进行测定;对喹(噁)啉-2-羧酸进行了均匀性、稳定性研究.结果表明,研制的喹(噁)啉-2-羧酸标准物质均匀性良好,稳定时间12个月,可以用于残留检测的定性和定量分析.     

Effect of CNTs on Activation Volume and Mobile Dislocation Exhaustion Rate of CNTs/Al under Compression Loading

In this study, stress relaxation compression tests were performed to investigate the strain rate sensitivity, activation volume and mobile dislocations in carbon nanotubes/aluminum (CNTs/Al) composites. The results reveal that, with the addition of CNTs, the strain rate sensitivity of CNTs/Al increased. Meanwhile, a smaller V^* of CNTs/Al compared with pure Al was attributed mainly to the CNT-Al interfaces and partly to the increased forest dislocations cutting activities in grain interior, which was related to the tendency of short ranges order formation during plastic deformation. The incorporation of CNTs also improved the dislocation storage capability and reduced the dislocation velocity, leading to a lower mobile dislocation exhaustion rate.     

Al-Zn-Mg-Cu合金新型等通道转角双向镦挤变形行为分析

以超高强度Al-Zn-Mg-Cu合金为研究对象,采用数值模拟和实验相结合的方法对其等通道转角双向镦挤过程进行分析。结果发现,变形过程可以分为近局部镦粗、剪切变形、最后填充三个阶段,变形结束后试样根据金属流动和网格畸变程度划分为小变形区、不变形区、剪切变形区、剧烈变形区。不同加载方式使变形区域发生不同程度偏移,上下冲头速度差越大,变形均匀性越差,速度比为1时可获得最大的应变量为3.97,且变形均匀性系数最低为1.89。同时,对不同路径下的多道次变形行为进行研究,发现4道次结束后,B路径比A路径变形更加均匀充分,其变形均匀性系数降低了29 %,剪切变形区占比提升了14 %。