Dumbbell Fluidic Tweezers for Dynamical Trapping and Selective Transport of Microobjects

Mobile microvortices generated by rotating nickel (Ni) nanowires (NW) have been reported as capable of inducing fluidic trapping that can be precisely focused and translated to manipulate microobjects. Here, a new design for significantly enhanced fluidic trapping is reported, which is a dumbbell (DB)‐shaped magnetic actuator, assembled by a Ni NW and two polystyrene microbeads. In contrast to the single mode of tumbling trapping possessed by Ni NW, the magnetic dumbbell is able to perform dynamical trapping and implement on‐demand transport of microobjects in three modes, i.e., tumbling, wobbling, and rolling. Experiments are conducted to demonstrate the robustness and efficacy of the fluidic trap by the DB actuator. And simulations using a finite element model compare the fluidic traps induced by NW and DB, followed by further discussion on the actuation and transport efficiency of NW and DB fluidic tweezers (FT). At last, some practical issues regarding the application of DB FT are addressed.     

基于时间相关单光子计数的非接触式荧光层析成像系统

基于时间相关单光子计数(TCSPC)技术原理,研究了一套面向早期乳腺癌检测的时域荧光层析成像系统,系统采用非接触式空间光扫描测量方式,相对于传统的光纤接触式测量方法,可增大空间采样量、减小测量误差、提高空间分辨率.通过仿体实验对系统的成像质量进行了验证,结果表明:单目标仿体实验能较好地对荧光产率与寿命进行重建;在双目标仿体荧光产率的重建中,可有效对中心距为20mm、边距为15mm的目标体进行分辨,且对不同浓度荧光剂目标的重建具有较好的线性.实验结果证明系统应用于乳腺检测的可行性,进一步发展可有望应用于临床乳腺成像中.     

承压水上开采工作面底板破坏规律相似模拟试验

 随着我国煤炭开采深度的增大,承压水上开采工作面底板破断、突水灾害正呈逐年递增的趋势。以峰峰矿区九龙矿深部承压水上开采工作面底板为研究对象,通过现场底板取芯、编录和室内试验,获得承压水上工作面底板含水层分布特征及底板岩层的力学参数,确保试验中现场参数的可靠性。采用自行设计的工作面底板水压模拟装置,进行承压水上工作面回采过程中顶、底板破断失稳特征的相似模拟试验,得到底板工作面回采过程中顶、底板应力变化规律。运用非接触的光学测量技术对全场位移值进行观测,得出底板位移场变化规律。通过“下三带”理论,计算九龙矿深部工作面底板岩层的最大破坏深度、承压水导升高度和有效隔水层厚度。模拟试验结果表明：九龙矿深部承压水上工作面开采底板存在明显的“三带”特征,采用新型的承压水模拟装置可以模拟承压水在采动作用下的卸压过程。     

用PSD精确测量软质低反光材料

介绍一种适用于软质低反光材料检测的半导体激光位置探测器ＰＳＤ,用半导体激光器和位置探测器件及相关光学数控系统来测量软质低反光材料,进行无接触式高精度测量,被测件表面不损伤,无擦痕、不变殂,测量精度高、分辨率高。     

微波网络驻波和衰减测量的误差分析

应用信号流图结合S参数分析了标网测量微波网络驻波和衰减的误差.推导出了N端口网络测量驻波和衰减时产生的最大测量误差公式.可供测试微波网络时作误差分析,也可供设计微波系统的人员在分配每个元件驻波和衰减参数时作参考.     

检测复杂内轮廓中圆弧面的新型光纤传感器特性研究

介绍了一种用于对复杂内轮廓检测的强度调制型光纤传感器,该传感器轮辐式的光纤排列结构,有利于补偿表面反射率不同和光源波动等给测量带来的影响.给出并分析了检测圆弧形内轮廓时传感器的特性.从仿真结果可见,这种传感器能较好地实现圆弧型轮廓的检测问题,具有结构简单、非接触、抗电磁干扰及适合于现场使用等优点.本文为强度调制型光纤传感器用于圆弧形曲线面及复杂柱状内轮廓表面工件的非接触检测提供了必要的理论基础和设计依据.     

Noncontact measurement of deep tissue absorption coefficient using Spatially Resolved Near‐Infrared Spectroscopy

We examined the influence of probe‐tissue distance on the relationship between the deep tissue absorption coefficient and the spatial profile of light intensity by Monte Carlo simulation and in vivo experiments, using noncontact spatially resolved near‐infrared spectroscopy (SRS). These results suggest that noncontact SRS can be reliably used for noncontact measurement of the absorption coefficient and oxygen saturation of deep tissues. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Flexible Smart Noncontact Control Systems with Ultrasensitive Humidity Sensors

The development of noncontact humidity sensors with high sensitivity, rapid response, and a facile fabrication process is urgently desired for advanced noncontact human–machine interaction (HMI) applications. Here, a flexible and transparent humidity sensor based on MoO₃ nanosheets is developed with a low‐cost and easily manufactured process. The designed humidity sensor exhibits ultrahigh sensitivity, fast response, great stability, and high selectivity, exceeding the state‐of‐the‐art humidity sensors. Furthermore, a wearable moisture analysis system is assembled for real‐time monitoring of ambient humidity and human breathing states. Benefiting from the sensitive and rapid response to fingertip humidity, the sensors are successfully applied to both a smart noncontact multistage switch and a novel flexible transparent noncontact screen for smart mobile devices, demonstrating the potential of the MoO₃ nanosheets‐based humidity sensors in future HMI systems.     

Fabricating method of SU-8 photoresist conical nozzle for inkjet printhead

A novel conical nozzle fabrication method for piezoelectric inkjet printhead is proposed based on the microelectromechanical system technology. By optimizing the exposure gap, exposure dose, postexposure bake (PEB), and development time, the SU-8 conical nozzle was fabricated. After thermal bonding with an open chamber, the piezoelectric inkjet printhead chamber was formed. The results show that the optimum SU-8 conical nozzle can be fabricated by applying exposure dose of 105?mJ/cm², exposure gap of 50?µm, PEB temperature of 65°C, PEB time of 10?min, and development time of 210?s. The final size of optimum conical nozzle is the large aperture of 30.46?±?1.17?µm, small aperture of 20.34?±?1.42?µm, and nozzle height of 45.38?±?1.02?µm.