原子力显微镜超微量注射检测的影响分析

微量注射与检测受到越来越广泛的关注和研究,例如细胞工程与基因工程中,采用显微注射其注射量对操作成功率影响巨大,注射量精确检测成为人们关注的课题。利用原子力显微镜具有纳米级高度分辨率的特点,设计悬臂装置对注射微滴重力产生的挠度进行检测,实现微滴量定量检测的目的。分析讨论影响微滴检测过程的扰动因素,其中采用悬挂机构有效抑制中高频扰动,观察注意到悬架式隔振系统水平方向的微小摆动对检测信号扰动不可忽视。研究中为抑制这种低频扰动对超微量注射检测的影响,设计液体阻尼器并采用增大水平阻尼与转动阻尼的方法使之得到有效地改善;进行皮升级注射量检测试验,结果表明所采用的基于原子力显微镜的超微量注射检测能够实现10～30 pL 微量注射检测。     

基于AFM的微滴检测装置悬臂长度对检测信号的影响

利用原子力显微镜（AFM）具有纳米级高分辨率的特点，采用聚酯悬臂感应微小液滴重量所产生的挠度，从而达到实时检测微滴量的目的。通过单片机控制CMOS管的方法产生正脉宽只有8～10的脉冲，来实现利盟（LEXMARK）喷墨头的可控喷射，从而产生检测所需的可控微滴。最后试验检测系统的信噪比，实验不同悬臂长度对检测信号的影响。     

高精度STM.IPC-205BJ型原子力显微镜的设计

在成功研制高精度IPC-205B型STM基础上对硬件设计和软件配备进行改进,研制开发了更高精度和应用更广的原子力显微镜.阐述该原子力显微镜的工作原理、组成及应用,详细介绍镜体的独特设计与控制过程、微悬臂的制作与工作过程.该样机采用简单适用的新型微悬臂,利用扫描隧道显微镜检测微悬臂的起伏,通过四维机械驱动和双压电陶瓷扫描,能够有效提高扫描精度、扩大扫描范围.该原子力显微镜的分辨力为:横向0.1 nm,纵向0.01 nm.给出该机型检测的几种样品的扫描图像.     

用交流电化学腐蚀法制备隧道电流型原子力显微镜微悬臂

隧道电流型原子力显微镜是在扫描隧道显微镜基础上发展起来的一种表面分析技术。微悬臂是原子力显微镜的关键元件，它的制备与安装质量直接影响隧道电流型原子力显微镜的实验结果，本文简单介绍隧道电流型原子力显微镜微悬臂的工作原理，讨论对微悬臂的要求，提出一种简单有效的微悬臂制作方法－交流电化学腐蚀法，给出了用交流电化学腐蚀法制备的微悬臂得到的石墨标样表面原子结构图象。     

一种高精度多功能双用原子力显微镜技术及应用

主要研究了一种基于高精度IPC-205B型扫描隧道显微镜(STM)的新型高精度多功能双用原子力显微镜(AFM)技术及其应用.阐述该原子力显微镜的工作原理、组成及应用,详细介绍了该AFM镜体的独特结构和新型微悬臂的制作及其检测方法.该AFM采用简单适用的新型微悬臂.并利用STM检测微悬臂的起伏,通过四维机械驱动和双压电陶瓷扫描,有效提高了扫描精度,扩大了扫描范围.该机型集AFM和STM功能为一体,其中STM可以单独使用.该机型检测精度可达:横向0.1 nm,纵向0.01 nm.并用该样机进行了样品表面形貌和隧道谱的实验研究.     

转基因微注射系统中注射量的控制技术

转基因微注射系统中DNA注射量的精确控制是构建微注射自动控制系统的关键。以微流体实验为基础，构建了气压电控式微注射量控制器，以注射压力、注射时间及注射针针管半径为控制参数，实现对DNA注射量高精度、高效率而又无污染性的控制。微注射的实验结果表明，建立在上述三参数上的微注射量的数学模型是可以实现的。由此说明采用气压电控式控制方式对微注射量进行控制，确为一条方便、高效的途径。     

复合型超精密表面形貌测量仪

研制了基于同一显微镜基体实现原子力探针扫描测量与非接触光学测量两种功能的复合型超精密表面形貌测量仪.分析了基于白光显微干涉原子力探针的测量方法、探针微悬臂变形量与白光干涉条纹移动量的关系以及探针微悬臂测量非线性误差的修正方法,和通过融合垂直扫描系统的位移量和悬臂梁变形量得到了原子力探针的工作方式.研制了三维精密位移系统...     

基于LIGA技术的光热驱动微开关研究

设计制作了一种三角形结构的金属材料光热驱动微开关.通过理论分析和ANSYS仿真,揭示了光热偏转量与三角形结构的微悬臂倾角之间的相互关系;基于同步辐射光源及LIGA技术,以金属镍(Ni)为基底材料,微加工制作出一个微悬臂长度1435μm、倾角6°的微开关器件;利用光热驱动控制与显微视频监控系统,进行了光热驱动及偏转量检测...     

基于光点偏转方法的原子力显微镜的研制

讨论了光点偏转方法检测微小位移的原理，建立了相应的光电检测系统，用于检测微悬臂（针尖）的微位移，并在此基础上研制了纳米级分辨率的原子力显微镜。仪器最大扫描范围可达2×2μm2。文中给出了部分样品的测试结果。     

一种高精度原子力显微镜的设计及应用

简述了重庆大学研制的原子力显微镜(AFM)样机的工作原理和应用，重点介绍了其镜体的独特设计。该样机采用扫描隧道显微镜检测微悬臂的起伏，通过四维机械驱动和双压电陶瓷扫描，有效提高了扫描精度，扩大了扫描范围，简单适用的微悬臂使操作大大简化。给出了用该机检测到的具有代表性的4种样品的表面形貌图。     

A femtogram resolution mass sensor platform based on SOI electrostatically driven resonant cantilever. Part II: sensor calibration and glycerine evaporation rate measurement

This paper presents mass measurements of glycerine beads performed by means of laterally resonant micro-cantilevers. The transducer architecture is based on a resonant cantilever electrostatically coupled by two parallel placed electrodes. Previous to glycerine measurements, a calibration of the mass sensor has been performed by measuring a standard mass based on latex spheres. From these measurements, a value of the mass responsivity is deduced. In addition, a study of the transducer phase noise has been carried out in order to determine the minimum detectable mass. Mass measurements experiments have been performed by detecting the change on the resonance frequency of the on-plane cantilever resonant mode, produced by locally deposited mass. Additionally, the mass losses detected on the calibrated transducer after glycerine drop deposition allowed determining its evaporation rate.     

Self-sensing piezoresistive cantilever and its magnetic force microscopy applications

A newly developed Si self-sensing piezoresistive cantilever is presented. Si piezoresistive cantilevers for scanning microscopy are fabricated by Si micro-machining technique. The sensitivity of the piezoresistive cantilever is comparable to the current laser detecting system. Topographic images are successfully obtained with the piezoresistive cantilever and some comparisons are made with the laser detecting system. Furthermore, the magnetic film (Co-Cr-Pt) is coated on the tip of the piezoresistive cantilever for magnetic force microscopy (MFM) application. The magnetic images are successfully obtained with the self-sensing MFM piezoresistive cantilever. The self-sensing piezoresistive cantilevers have been successfully applied in scanning probe microscopy and MFM.     

激光光强分布对原子力显微镜中光学偏转法检测结果的影响

从光学偏转超微力检测原理出发,严格地分析了在激光光源具有一定空间光强分布的情况下其检测的结果。我们发现激光源的空间光强分布在超微力检测条件下对检测结果没有影响,即其PSD的输出信号完全正确地反应了悬臂梁的受力大小。但是,PSD所检测光斑的重心位置对应的光线将随悬臂梁受力大小的不同而不同。本文给出了入射光经弯曲悬臂梁反射后空间光强分布变化的计算方法和计算实例,并提出了进一步从反射光束中提取上述变化信息并加以应用的建议     

悬臂式坐标测量机的设计和误差补偿

介绍了一种自主设计用于结晶器内腔测量的悬臂式三坐标测量机,分析了测量机的机械结构组成及各项几何误差。建立测量机的准刚体测量模型,以补偿各项主要误差,经过实验证明能够有效提高测量机精度。     

On the electromechanical modelling of a resonating nano-cantilever-based transducer

An electromechanical model for a transducer based on a lateral resonating cantilever is described. The on-plane vibrations of the cantilever are excited electrostatically by applying DC and AC voltages from a driver electrode placed closely parallel to the cantilever. The model predicts the static deflection and the frequency response of the oscillation amplitude for different voltage polarization conditions. For the electrostatic force calculation the model takes into account the real deflection shape of the cantilever and the contribution to the cantilever-driver capacitance of the fringing field. Both the static and dynamic predictions have been validated experimentally by measuring the deflection of the cantilever by means of an optical microscope.     

基于槽式悬臂梁结构的微质量传感器设计

压电式微质量传感器的测试精度直接依赖于结构频率对质量变化的灵敏程度。本文利用对称槽型梁和压电薄膜组成的对称敏感结构,提出了一种提高传感器灵敏度的结构设计方法,并设计了一种高精度谐振式微质量传感器。建立了结构频率变化对吸附质量敏感性的分析模型,并研究了槽型截面参数、自振频率及振动模态对灵敏度的影响。与矩形截面结构进行了仿真与实验对比,结果表明,相同几何尺寸参数下,槽型截面悬臂梁的一阶自振频率为1 851 Hz,矩形截面悬臂梁的一阶自振频率为1 610 Hz,相应的传感器灵敏度则分别为3.12×10⁴ Hz/g和1.5×10⁴ Hz/g,前者是后者的2倍。该项设计为提高微质量传感器灵敏度提供了一种新思路。     

Exploiting cantilever curvature for noise reduction in atomic force microscopy

Optical beam deflection is a widely used method for detecting the deflection of atomic force microscope (AFM) cantilevers. This paper presents a first order derivation for the angular detection noise density which determines the lower limit for deflection sensing. Surprisingly, the cantilever radius of curvature, commonly not considered, plays a crucial role and can be exploited to decrease angular detection noise. We demonstrate a reduction in angular detection shot noise of more than an order of magnitude on a home-built AFM with a commercial 450 μm long cantilever by exploiting the optical properties of the cantilever curvature caused by the reflective gold coating. Lastly, we demonstrate how cantilever curvature can be responsible for up to 45% of the variability in the measured sensitivity of cantilevers on commercially available AFMs.     

Nanochemical surface analyzer in CMOS technology

We have developed an atomic force microscopy (AFM) cantilever system, fabricated using a standard CMOS process and a few post-processing steps, capable of detecting the difference between hydrophilic and hydrophobic samples for the purpose of nanochemical surface analysis. The fully integrated cantilever comprises a thermal actuator for cantilever deflection and a Wheatstone bridge to sense cantilever bending, thus obviating the need for cumbersome laser detection and external piezoelectric drives. Glass microspheres have been affixed to the cantilevers and, were either modified with a self-assembled monolayer to form hydrophobic tips, or left unmodified for hydrophilic tips. Force-distance curves have been used to measure the force between the functionalized/unfunctionalized tips and hydrophobic/hydrophilic sample surfaces. In an optimization step three different Wheatstone bridge sensors have been designed and characterized; best Wheatstone bridge sensitivity is 8.0 microV/nm with a 713 nm/mW actuator efficiency.     

Piezoelectric based resonant mass sensor using phase measurement

The paper presents design, development and testing of a resonant sensor to measure mass in the range of 0-12 g. The sensor is built using cantilever structure with piezoelectric excitation, sensing and microcontroller based closed loop electronics. The sensor measures the unknown mass by measuring the shift in resonance frequency of the cantilever beam. The shift in resonance frequency for a change in mass is detected by measuring the phase difference between the piezoelectric sensor output and actuator input using microcontroller. The proposed measurement system is simple and accuracy is found to be ±1.2% of full scale deflection.