实践十号卫星项目——热毛细对流振荡特征的地面研究

上部开口环形液池在水平径向温度梯度作用下会出现内部温度和自由面的振荡,本文研究了二者发生的临界条件.环形液池内柱加热外壁制冷,以0.5℃/min的速率线性升温得到水平径向温差,T型热电偶测量液层内部单点温度,高精度激光位移传感器测量液层自由面某点形变.随两端温差增加,当超过某一临界温度△T_(cr)时,开始出现振荡.实验结果表明,对同一种硅油,两种振荡的临界条件随液层厚度具有相同的变化趋势.对不同普朗特(Prandtl)数(Pr)的硅油,振荡临界条件临界马兰哥尼数(Ma_(cr))随着邦德数(Bo)的增加而变大.本文工作是中国科学院科学先导专项SJ-10返回式科学实验卫星项目-热毛细对流表面波空间实验研究的地面研究结果,该工作为空间实验提供前期的基础科学研究数据和实验保障.     

两层液体Bénard-Marangoni对流的实验研究

采用粒子图像测速技术(PIV)对两层流体B(en)ard-Marangoni对流进行了实验研究.研究了各种不同厚度比下的临界对流模式,同时研究了在温差变大时向超临界对流模式转化过程.实验结果表明,界面张力对各种对流模式的形成和转变具有重要的作用.     

两种含氟三氮烯显色剂FNDAA与FFDAA的合成及其与镉显色反应的研究

报道了两种新显色剂 4 氟 4′ 硝基苯基重氮氨基偶氮苯 (FNDAA)和 4 氟 4′ 氟苯基重氮氨基偶氮苯 (FFDAA)的合成、性质及其与Cd(Ⅱ )的显色反应。在弱碱性介质中 ,TritonX 10 0存在下两种试剂均与Cd(Ⅱ )形成络合比为 3∶1的橙红色络合物。对FNDAA ,ε4 92 =1.5 4× 10 5 L·mol- 1·cm- 1,对FFDAA ,ε4 90 =1.17× 10 5 L·mol- 1·cm- 1。镉量分别在 0 15和 0 2 5 μg/2 5ml范围内遵守比耳定律。FNDAA有较好的选择性 ,用于测定环境水标样中镉含量 ,结果满意。     

微重力环境下无限长柱体内角毛细流动解析近似解研究

应用同伦分析法研究无限长柱体内角毛细流动解析近似解问题,给出了级数解的递推公式.不同于其他解析近似方法,该方法从根本上克服了摄动理论对小参数的过分依赖,其有效性与所研究的非线性问题是否含有小参数无关,适用范围广.同伦分析法提供了选取基函数的自由,可以选取较好的基函数,更有效地逼近问题的解,通过引入辅助参数和辅助函数来调节和控制级数解的收敛区域和收敛速度,同伦分析法为内角毛细流动问题的解析近似求解开辟了一个全新的途径.通过具体算例,将同伦分析法与四阶龙格库塔方法数值解做了比较,结果表明,该方法具有很高的计算精度.     

双液滴热毛细迁移的实验研究

在地面实验中，研究在竖直向上温度梯度流场中，双液滴的热毛细迁移运动和它们间的相互 作用. 豆油和硅油分别作为实验系统的母液和液滴. 液滴迁移轨迹被记录和分析. 实验结果 表明，大小液滴的实验迁移速度均小于理论迁移速度；两个液滴之间的相互作用对小液滴的 影响更为明显，使之出现倾斜``8'字的迁移轨迹；两个液滴的运动速度都出现了振荡现象， 小液滴可能出现短时反向迁移. 实验结果与数值模拟结果较为相似，但尚有差异，需要进一 步进行研究.     

Experimental Investigation of Influence of Interfacial Tension on Convection of Two-Layer Immiscible Liquid

Bdnard-Marangoni convections of two-layer fluids heated from the bottom are investigated experimentally with a particle imagine velocimetry. The flows are visualized from the side, and various velocity fields near the onset of convection, such as three-layer vortex convective patterns, are observed when the depth ratio varies in a wide range. A new classification of the convective patterns is proposed with more detail than in previous studies. The analysis of the results indicates that the interface tension greatly influences the motion intensities of the bottom and top layers. The dimensionless wave number increases with the Bond number when the motion in the top layer is not more intense than that in the bottom layer, which agrees with the theoretical prediction.     

一种大视角重建折射率场的简易方法

本文设计了一种双照明光双参考光的全息干涉系统,能在一块干板上一次记录90°连续视角范围的干涉图.通过计算机模拟的噪声数据,考查了一种简单重建方法——卷积法的重建精度和抗噪声性能;通过以上系统获得的试验数据,重建了一个截面上的温度分布,并与热电偶测得的值进行了比较.     

Experimental Study on Liquid Free Surface in Buoyant-Thermocapillary Convection

We investigate the surface deformations of buoyant-thermocapillary convection in a rectangular cavity due to gravity and temperature gradient between the two sidewalls. The cavity is 52mm×42 mm in horizontal cross section, the thickness of liquid layer h is changed from 2.5 mm to 6.5 mm. Surface deformations of h = 3.5 mm and 6.0mm are discussed and compared. Temperature difference is increased gradually, and the flow in the liquid layer will change from stable convection to unstable convection. Two kinds of optical diagnostic system with image processor are developed for study of the kinetics of buoyant-thermocapillary convection, they give out the information of liquid free surface. The quantitative results are calculated by Fourier transform and correlation analysis, respectively. With the increasing temperature gradient, surface deformations calculated are more declining. It is interesting phenomenon that the inclining directions of the convections in thin and thick liquid layers are different. For a thin layer, the convection is mainly controlled by thermocapillary effect. However, for a thick layer, the convection is mainly controlled by buoyancy effect. The surface deformation theoretically analysed is consistent with our experimental results. The present experiment proves that surface deformation is related to temperature gradient and thickness of the liquid layer. In other words, surface deformation lies on capillary convection and buoyancy convection.     

配液结晶法制备溶菌酶蛋白质晶体的生长机理研究

采用配液结晶法制取了溶菌酶蛋白质晶体, 使用动态光散射测量了溶液中聚集体的颗粒度几率分布; 使用Zeiss显微镜测定了溶菌酶(110)晶面的生长速度. 实验表明: 随着蛋白质和NaCl浓度的增加, 溶液中聚集体的颗粒尺寸也相应增加. 随着反应时间的增加, 溶菌酶分子在溶液中的聚集反应, 逐渐达到平衡; 在蛋白质和NaCl浓度较高时, 溶菌酶晶体的(110)面生长较快, 而在蛋白质和NaCl浓度较低时, 该晶面生长较慢. 基于二维成核生长机理, 从晶体生长动力学理论方程出发, 计算了二维成核的形成能α＝4.01×10^－8 J•cm^－2.