Frequency characteristics of stiffness and damping effect of ferro fluid bearing

Damping characteristics and frequency characteristics of ferro fluid bearing (FFB) spindles were measured using a high-frequency vibration base driven by a piezo actuator. Using the high-frequency vibration base, high-frequency excitation was added to ferro fluid bearing spindles mounted on the vibration base, and it was proved that ferro fluid bearing spindles have effective damping. And the damping effect became larger with higher spindle rotational speed. Also we have measured spindle runout of a ferro fluid bearing spindle using a lock-in amplifier to increase S/N ratio and succeeded to measure nano meter order displacements.     

基于ABAQUS软件的微米级金属材料性能研究

为工程实践中迫切需要解决微米和亚微米量级的设计与制造问题,文章中运用MSG塑性理论利用Abaqus软件对铝合金的强度及均匀延伸率进行了比较系统的研究;运用有限单元法分析了MSG应变梯度本构方程和经典的弹塑性本构方程对不同晶粒尺寸的铝合金的应力应变关系;模拟不同晶粒尺寸的铝合金的强度及均匀延伸率。结果表明随着晶粒尺寸的减小,屈服强度、应变硬化明显增加,延伸率却往往越小。对于该问题的研究探索,将是解决材料强度与均匀伸长率这对矛盾体的问题关键,同时,为科研工作者提供了新方法和新途径。     

离心成型钢纤维混凝土劈裂抗拉强度的尺寸效应

基于不同高度试件的劈裂抗拉试验结果,研究了离心成型中速阶段离心时间和离心加速度、骨料级配、钢纤维长度、钢纤维体积率等因素对钢纤维混凝土劈裂抗拉强度尺寸效应的影响.通过对比分析,提出了以高度为150 mm的试件为标准的劈裂抗拉强度尺寸效应换算系数,可供实际应用参考.     

基于风险管控的历史遗留硫磺冶炼废渣综合治理效果

为解决赤水河源头流域(云南段)历史遗留硫磺冶炼废渣40多年无序堆积导致流域水体持续酸化的污染问题,通过对“自然衰减”“异位修复”“风险管控”等治理途径分析,提出“风险管控+生态修复”模式开展了该区域内酸性废渣和废水的示范工程治理。在查明治理区域污染因子的基础上,采取“废渣防流失、复合阻隔控制、适生植物配比、污水收集处理和运行监测管理”的集成风险管控技术,分析工程实施前、实施中和实施后的固废属性,以及地表水、地下水和废渣渗滤液中污染因子的变化。结果表明：在投加0.35%～0.65%比例生石灰条件下,固废属性从第Ⅱ类一般工业固废改性为第Ⅰ类一般工业固废;工程完工时,地下水pH即可达标,硫酸盐超标倍数从最大5.3倍削减至1.2倍;工程实施3个月后,渗滤液pH稳定达标,硫酸盐超标倍数从最大3.2倍削减至1.7倍;工程实施7个月后地表水pH达标。基于风险管控的历史遗留硫磺冶炼废渣综合治理,能够满足管控目标,并初步完成了技术推广和应用。     

浅谈混凝土抗压强度试验中环箍效应对试件影响范围的确定

利用静态应变仪及分析软件在混凝土抗压强度试验时对混凝土试件产生的横向变形数据进行采集和分析,得出沿混凝土试件高度范围内,距压板越远,环箍效应对试件的影响越小,反之亦然。环箍效应对混凝土试件的影响集中在距压板范围内。     

When viewing variations in paintings by Mondrian, aesthetic preferences correlate with pupil size.

Observers consciously prefer Mondrian's paintings in their original orientation compared with a rotated position—the “oblique effect” (Latto, Brain, & Kelly, 2000). However, this finding's premise, that all vertical–horizontal orientations of the thick black lines in Mondrian's oeuvre are preferred, overlooks the fact that the overall balance of these images is also altered when they are reoriented. Thus, balance may regulate the oblique effect, which might influence conscious aesthetic preferences. To address this issue, we explore Hess's (1965, 1972) claim that observers will unconsciously increase their pupil diameter to pleasing images and constrict it to unpleasant images. We overcame Hess's methodological limitation of not keeping his images' luminances and contrast constant across conditions by presenting eight Mondrian paintings (1921–1944) to 30 observers on a CRT for 20 s each in either their original or seven rotated positions. Simultaneously, we measured their pupil size while asking them to report how (dis)pleasing they found each image. We found both evidence for the oblique effect (where image rotation hampers preference) and a correlation between this consciously reported aesthetic preference and unconsciously derived pupil size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

日常生活的电磁辐射与生物效应

本文简单介绍了电磁辐射和生物效应的原理和现象以及相关的研究情况和标准.包括:电磁辐射对机体的影响,电磁辐射对人体影响的研究情况,行业的卫生标准和生活中与电磁辐射接触的机会.     

脉宽调制器单粒子效应测试系统研制

本文在分析脉宽调制器(PWM)单粒子效应主要失效模式的基础上,研制了具备频率异常测试、占空比异常测试和参考电压测试功能的PWM单粒子效应测试系统,并在中国原子能科学研究院HI-13串列加速器上开展了单粒子效应试验。试验结果表明:单粒子效应会导致PWM输出信号的脉冲丢失和占空比改变,脉冲丢失时间和占空比改变的持续时间有时可达数ms;UC1825AJ型PWM的单粒子效应LET阈值约为4.4MeV·cm2·mg-1,UC1845AJ型PWM的抗单粒子性能受工艺批次的影响较大。     

结晶器漏钢预报系统

对连铸机结晶器漏钢预报系统的控制原理,功能,结构进行了说明,该系统对提高连铸机作业率具有重要意义。     

多种金属氧化物混合物的固溶体的穆斯堡尔效应及XRD分析研究

在αFe_2O_3中依次累积加入K_2O、Cr_2O_3、CuO、MGO和SiO_2形成不同混合物,在空气中800℃活化焙烧5h后,发现αFe_2O_3和所加氧化物之间发生了不同的反应,生成不同的化合物。该结果有助于进一步理解这些氧化物作为助剂和载体的作用。