液冷微通道内相变微胶囊的壁面温升抑制特性数值模拟

相变微胶囊悬浮液是一种新型的蓄热-传热功能流体,目前对相变微胶囊与基液流固传递作用认识的欠缺,导致宏观上对悬浮液流动传热性能的研究结果存在较大的差异.为此,本文采用任意拉格朗日-欧拉方法模拟相变微胶囊在液冷微通道内流固作用下的流动传热特性,对比普通颗粒及相变胶囊对液冷微通道壁面温升的抑制作用,考察胶囊位置、形状及数量对壁面温升抑制的影响.结果表明:胶囊及颗粒均对它们上游区域的壁面温升产生抑制作用,而胶囊的相变使得抑制效果更加明显;胶囊越靠近壁面自旋运动越快,越有利于流体与壁面的换热,对壁面温升抑制效果越强,尤其是靠近受热面时;相比椭圆形胶囊,圆形胶囊自旋运动更激烈,对壁面温升抑制效果更优;随着加热区内胶囊数的增加,最大抑制效果在逐渐提升.     

Magnetostriction of Fe81Ga19 oriented crystals

The effect of the orientation on the magnetostriction in Fe 81 Ga 19 alloy has been investigated experimentally and theoretically.The Fe 81 Ga 19 [001] and [110] oriented crystals were prepared and the magnetostriction was measured under different pre-stress.The saturation magnetostriction of the [001] oriented crystal increases from 170×10-6 to 330×10-6 under the pre-stress from 0 to 50 MPa.The [110] oriented crystal has a saturation magnetostriction from 20×10-6 to 140×10-6 with the compressive pre-stress from 0 to 40 MPa.The magnetostriction of [001] and [110] oriented crystals has been simulated based on the phenomenological theory.The domain rotation path has been determined and the resultant magnetostriction calculated under different pre-stress.The experimental and simulated results both show that the [001] oriented crystal exhibits better magnetostriction than [110] oriented crystal.The enhancement of the saturation magnetostriction by the compressive pre-stress in the [110] oriented crystal is higher than that in the [001] oriented crystal.     

大视场白光干涉测量系统及性能研究

基于国产化的2倍迈克尔逊型干涉物镜组,优选配置0.5倍适配镜,对白光LED照明光源进行带通滤波参数的仿真估算和实验性能比较,构建了整套大视场白光干涉精密测量装置系统并进行了实验测试,通过白光干涉轴向响应实验曲线确定了中心波长。实验结果表明：通过光谱滤波获得了较为理想的白光干涉轴向响应曲线;系统的水平最大视场达到了14 mm;高度为2.04μm和20.43μm的标准台阶样品的测量结果分别为2.05μm和20.47μm,10次测量重复精度（标准差）分别为12 nm和16 nm。对粗糙度样板、微机电系统传感结构和半导体晶圆膜层进行了实测,表明所研制的系统装置在三维光学无损精密检测领域的应用具有可行性。