基于声表面波纸基微流器件研究

为了降低工艺要求和制作成本,提出了压电基片上纸基微流器件制作方法。采用焊锡丝构建微通道图案,通过聚二甲基硅氧烷(PDMS)固化、剥离焊锡丝、填入棉线、棉线吸收未固化PDMS等工艺过程,将图案转印于纸基片,并贴合于128°YX-LiNbO_3压电基片上。实验结果表明,电信号功率为27.3 dBm时,在研制器件上实现淀粉显色反应,验证其微流分析功能。     

基于声波的微粒操控型微流控芯片仿真分析

利用有限元仿真软件COMSOL,对基于声表面行波(tsaw)粒子分选芯片及体声波(baw)粒子富集芯片进行了分析并加以实验验证.在仿真软件中分别模拟声表面行波粒子分选芯片的声波传播、声场形成、粒子轨迹以及体声波粒子富集芯片的声场形成、粒子轨迹,分析其运作机理,对肉眼不可见的声波、声场分布做出可视化效果.实验结果说明这两种芯片基于不同原理,都可对微米级的硅球完成可控的操作,并对于后续的器件创新和优化打下基础.     

微流控拉曼检测芯片的制备与应用

微流控芯片系统具有高效率、低损耗、高安全系数、高灵敏度等优势,表面增强拉曼散射(SERS)光谱具有灵敏度高以及指纹效应强等优点。从两方面对微流控拉曼检测芯片进行综述:微流控芯片通道和SERS基底的制备以及微流控拉曼检测芯片的集成与应用。最后讨论了SERS微流控芯片在便携化应用方面的挑战和机遇,并对整个领域的未来发展方向与前景进行了展望。     

Elucidation of polyurethane dispersions in a batch rotor-stator mixer

In this study, the effect of high energy input from mechanical agitation, provided with a high shear rotor-stator, on the drop size and the drop size distribution (DSD) of aqueous polyurethane (PU) dispersions is investigated. The effect of the dispersed phase volume fraction (ϕ) on the DSD of aqueous PU dispersions is also examined to understand the fundamental characteristics that result from the high shear mixing. DSD is measured by using either a high magnification video probe or dynamic light scattering, depending on the range of drop sizes. For the PU without any ionic content, the distributions appear to be bimodal with rather large drop sizes. The mean sizes of the first and second modes are about 10 and 22 μm, respectively. For the PU with an ionic content, the mean drop sizes are approximately 80 nm. The distributions reveal that functional chemistry plays a more dominant role in the process of making PU dispersions than the mechanical agitation, and that ϕ has a weak effect on the mean drop sizes. The results further suggest that mechanical agitation can be used to control the breadth of the distributions.     

热压法快速制作微流控芯片模具

提出了一种微流控芯片模具的快速批量制作方法。应用光刻与湿法腐蚀技术制作玻璃母模,然后采用热压成形技术批量制作聚甲基丙烯酸甲酯(PMMA)阳模,再利用阳模浇模、键合批量制作聚二甲基硅氧烷(PDMS)微流控芯片。结果表明,该法制作的PMMA模具及复制得到的PDMS芯片平整度好、一致性高,其沟道宽度和深度的相对标准偏差分别小于0.5%和1.5%。     

微流控聚合物链式反应芯片的多色荧光检测

为了实现微流控芯片上多目标DNA片段的同时检 测,建立了基于光棒匀光结构的微流控芯片多色 荧光检测系统。根据微流控芯片中的聚合物链式反应(PCR)反应腔的特点,设计了基于超亮 白光LED模组、光棒、二向色镜 和CCD的正交型荧光检测系统。CCD可一次采集微流控芯片上所有PCR反应腔中的荧光信号 ,通过滤光 片轮组合的变换,可实现多种荧光标记物的同时检测。采用荧光素钠溶液对激发光的均匀性 进行了测试, 激发产生的荧光图像均匀度达到93.99%,可满足微流控芯片上多反应 腔同时检测的需求。同时,以pUC-18人工质粒DNA作为标准品,开展了微流控荧光PCR生物实验,对系统性能进行验证。实验结 果表明:微 流控PCR反应腔的 DNA浓度变化与荧光信号的变化相一致,pUC-18样品的检测限达到0.05pg/uL,扩增 效率为97.28%,熔解曲线显示无引物二聚体产生,特异性好,达到了 商业化仪器的水平。     

基于声表面波形状记忆合金微阀研究

研制了一种声表面波控制的形状记忆合金微阀。在128°YX-LiNbO3基片上光刻叉指换能器,其激发的声表面波加热压电基片上石蜡油,使弯曲的形状记忆合金线伸展,促使与其连接的聚二甲基硅氧烷微通道壁发生形变,截止微通道,实现微阀从开态向关态转变。撤除电信号,形状记忆合金线温度下降,恢复软性,在硬质塑料薄片的恢复力作用下,微阀重新由关态转为开态。以流体输运为实验对象进行微阀开关实验,结果表明,声表面波可有效控制形状记忆合金微阀的开关操作,在28.5dBm电信号功率作用下,微阀关闭时间为40.4s。     

快速检测病原菌含量的简易微流控系统

针对现有水产养殖病原菌检测时效性差、自动化程度低的缺点,提出了一种快速检测水产养殖病原菌含量的简易微流控系统研究方法。该系统将微电极构造于微流控芯片通道底部并与数字阻抗测量电路连接,通过在磁珠表面包被水产病原菌抗体,利用外部高斯磁场控制诱导磁珠捕获水产病原菌,并将水产病原菌与磁珠结合体带至微电极阵列,通过在电极端构建基于阻抗测量的计数电路,从而有效检测水产病原菌含量。研究结果表明该系统能够有效测量水产病原菌的含量,检测时间由传统的平板计数法48 h减少至30 min,检测效率提高为原来的60多倍,检出限相比现有的微流控阻抗法缩小100倍。     

Quantification of laminar mixing in the kenics static mixer: An experimental study

The laminar flow field in a Kenics KM static mixer has been studied using laser induced fluorescence and digital image analysis. Mixing was quantified by measurement of the number average striation thickness, variance of striation widths and interfacial area, for elements of length to diameter (L/D) ratios of 0.8, 1.0, 1.5 with 90° twist per element. From flow visualisations, transitions were observed in the flow where vortices developed above the first and second elements at Reynolds numbers of 43 and 90 for L/D = 0.8 and Reynolds numbers of 55 and 105 for L/D = 1.0. It was found that these vortices did not appreciably enhance mixing based on striation thickness and variance of striation widths measurements after 4 to 5 elements. The influence of viscosity ratio showed a viscosity ratio (dyed stream/bulk stream) of I had faster interfacial area growth and created more uniform mixtures compared to a viscosity ratio of 0.2 for flow rate ratio of 0.2.