Fabrication of high precision microstructure using ICP etching for capacitive inclination sensor

Capacitive inclination sensors have the advantage because it could easily provide a linear analog output with respect to inclination. Since the dimensions of the sensing region are very small, then this sensor is expected to be widely used in fields where efficient and reliable position control is a primary factor to be considered if this sensor could be mass produced at low cost. Therefore, we proposed fabrication process based on transfer to resin using mold. We successfully fabricated a micro capacitive inclination sensor by a combination of a resin forming method and a mold. The sensor consists of a gap distance of 80 μm between its electrodes. The sensor detects difference of capacitance, which varied with movement of silicone oil accompanying with inclination. When the sensor was inclined, linear analog output was obtained within the range of ?45 to +45°     

Analyzing complex FTMS simulations: a case study in high-level visualization of ion motions

Current practice in particle visualization renders particle position data directly onto the screen as points or glyphs. Using a camera placed at a fixed position, particle motions can be visualized by rendering trajectories or by animations. Applying such direct techniques to large, time dependent particle data sets often results in cluttered images in which the dynamic properties of the underlying system are difficult to interpret. In this case study we take an alternative approach to the visualization of ion motions. Instead of rendering ion position data directly, we first extract meaningful motion information from the ion position data and then map this information onto geometric primitives. Our goal is to produce high-level visualizations that reflect the physicists' way of thinking about ion dynamics. Parameterized geometric icons are defined to encode motion information of clusters of related ions. In addition, a parameterized camera control mechanism is used to analyze relative instead of only absolute ion motions. We apply the techniques to simulations of Fourier transform mass spectrometry (FTMS) experiments. The data produced by such simulations can amount to 5 10(4) ions and 10(5) timesteps. This paper discusses the requirements, design and informal evaluation of the implemented system.     

Entrance effect on ion transport in nanochannels

We investigate the effect of the surface charge at channel entrances upon ion conductance, which has been overlooked in the study of nanofluidics. Nonlinear ion transport behaviors were observed in 20-nm thick nanochannels having opposite surface charge polarity on the entrance side-walls with respect to that in the nanochannel. The heterogeneous distribution of surface charge at the channel entrance functions as a parasitic diode, which can cause ion current saturation under high voltage biases. Such effect becomes crucial at low bath concentration at which the electric double layers originated from the bath sidewalls pinch off the channel entrance. The experimental results are clarified by theoretical calculations based on 2D Poisson–Nernst–Planck equations. With such strong effect on ionic conductance of nanochannels, the change of surface charge polarity at the entrance sidewalls may find applications in chemical and biological sensing.     

CTViz: A tool for the visualization of transport in nanocomposites

A visualization tool (CTViz) for charge transport processes in 3-D hybrid materials (nanocomposites) was developed, inspired by the need for a graphical application to assist in code debugging and data presentation of an existing in-house code. As the simulation code grew, troubleshooting problems grew increasingly difficult without an effective way to visualize 3-D samples and charge transport in those samples. CTViz is able to produce publication and presentation quality visuals of the simulation box, as well as static and animated visuals of the paths of individual carriers through the sample. CTViz was designed to provide a high degree of flexibility in the visualization of the data. A feature that characterizes this tool is the use of shade and transparency levels to highlight important details in the morphology or in the transport paths by hiding or dimming elements of little relevance to the current view. This is fundamental for the visualization of 3-D systems with complex structures. The code presented here provides these required capabilities, but has gone beyond the original design and could be used as is or easily adapted for the visualization of other particulate transport where transport occurs on discrete paths.     

Numerical solution of a nonlocal identification problem for nonlinear ion transport

A numerical method for the solution of a parameter identification problem in a nonlinear non-self-adjoint two-point boundary value problem with an additional nonlocal condition defining the parameter is presented. The equation arises in the modelling of an experiment known as chronoamperometry for the study of kinetics and mass-transfer in electrochemical events. The algorithm is based on the reformulation of the identification problem as a nonlinear fixed-point problem involving the concentration flux of the reduced species. The linearized boundary value problem is shown to have a unique solution with the unknown parameter uniquely determined by the flux. The linearized BVP is solved using finite differences and the fixed-point is found using the α-bisection method. The results of computational experiments are presented and their physical significance is discussed.     

3D visualization of solar wind ion data from the Chang'E-1 exploration

Chang'E-1 (abbreviation CE-1), China's first Moon-orbiting spacecraft launched in 2007, carried equipment called the Solar Wind Ion Detector (abbreviation SWID), which sent back tens of gigabytes of solar wind ion differential number flux data. These data are essential for furthering our understanding of the cislunar space environment. However, to fully comprehend and analyze these data presents considerable difficulties, not only because of their huge size (57 GB), but also because of their complexity. Therefore, a new 3D visualization method is developed to give a more intuitive representation than traditional 1D and 2D visualizations, and in particular to offer a better indication of the direction of the incident ion differential number flux and the relative spatial position of CE-1 with respect to the Sun, the Earth, and the Moon. First, a coordinate system named Selenocentric Solar Ecliptic (SSE) which is more suitable for our goal is chosen, and solar wind ion differential number flux vectors in SSE are calculated from Geocentric Solar Ecliptic System (GSE) and Moon Center Coordinate (MCC) coordinates of the spacecraft, and then the ion differential number flux distribution in SSE is visualized in 3D space. This visualization method is integrated into an interactive visualization analysis software tool named vtSWIDs, developed in MATLAB, which enables researchers to browse through numerous records and manipulate the visualization results in real time. The tool also provides some useful statistical analysis functions, and can be easily expanded.     

一种新型电容式力矩传感器设计

为准确、快速地检测力矩,提出了基于电容边缘效应的差动式新型力矩传感器设计.由机械本体和印制电路板(PCB)组成,机械本体上2个感应动电极与PCB上2个对应的感应静电极互相垂直,且为差动式结构.通过电容量/数字转换器检测垂直极板间的电容量,得到“力矩/电容量”转换关系.以商用转矩转速传感器作为标准力矩仪对力矩传感器进行标定与实验验证,结果表明:差动式电容力矩传感器具有较高的灵敏度、重复度和线性度等优点,其灵敏度约为非差动式的2倍且非线性误差更小.     

射频电容式传感器的研究与应用

射频电容式传感器是近年来快速发展的新型传感器之一 ,特别在石油行业的油品含水量测量方面更得到了广泛的应用。论述了该传感器的测量原理 ,针对其复杂的测量环境对它的敏感探头进行了特殊设计 ,并给出了其先进的全遥控式测量仪器的应用实例。     

硅微电容式二维加速度传感器的加工与测试

设计了一种基于体硅加工技术的单敏感质量元差分电容式二维加速度传感器,并采用硅-玻璃静电键合、ICP工艺释放等技术完成了二维加速度传感器的加工.测试结果表明:该二维加速度传感器两个检测方向上的灵敏度基本一致,线性度较好,交叉干扰较小.X、Y方向的灵敏度分别为58.3 mV/gn、55.6 mV/gn;线性相关系数分别为0.9968、0.9961,交叉灵敏度分别为6.17％、7.82％.     

Towards a unified linear kinetic transport model with the trace ion module for EIRENE

Linear kinetic Monte Carlo particle transport models are frequently employed in fusion plasma simulations to quantify atomic and surface effects on the main plasma flow dynamics. Separate codes are used for transport of neutral particles (incl. radiation) and charged particles (trace impurity ions). Integration of both modules into main plasma fluid solvers provides then self-consistent solutions, in principle. The required interfaces are far from trivial, because rapid atomic processes in particular in the edge region of fusion plasmas require either smoothing and resampling, or frequent transfer of particles from one into the other Monte Carlo code. We propose a different scheme here, in which despite the inherently different mathematical form of kinetic equations for ions and neutrals (e.g. Fokker–Planck vs. Boltzmann collision integrals) both types of particle orbits can be integrated into one single code. We show that the approximations and shortcomings of this “single sourcing” concept (e.g., restriction to explicit ion drift orbit integration) can be fully tolerable in a wide range of typical fusion edge plasma conditions, and be overcompensated by the code-system simplicity, as well as by inherently ensured consistency in geometry (one single numerical grid only) and (the common) atomic and surface process modules.     

电容式微加工超声传感器（cMUT）的有限元仿真

介绍了电容式微加工超声传感器(cMUT)的基本结构和工作原理.同时使用有限元方法对cMUT的运行情况进行模拟.提出了两个ANSYS模型来阐述cMUT的塌陷电压与谐振频率.一个3D模型用来阐述制造过程中的残余应力对cMUT谐振频率的影响.另外一个3D模型阐述不同的运行环境对cMUT的谐振频率的影响.     

基于电容式套管的电子式电压传感器的研制

在分析电容式套管结构和分压原理的基础上,采用传感器与一次高压设备融合技术,设计了基于套管次末屏以及末屏分压的电压监测传感器,并通过实验验证了该传感器的有效性.测试结果表明:该传感器能可靠地采集套管传过来的工频电压和冲击电压信号.     

单壁碳纳米管的猝灭效应用于银离子的检测

基于单壁碳纳米管(SWNTs)良好的猝灭性能,发展了利用单链DNA(ssDNA)和单壁碳纳米管的荧光探针用于对Ag+进行检测的方法。其中富含C碱基的FAM标记的单链DNA(ssDNA)与单壁碳纳米管(SWNTs)发生π*π间的相互作用后,其荧光被猝灭。当有Ag+加入时,ssDNA会由于C-Ag+-C作用形成发夹结构,刚性增强从而脱离碳纳米管使荧光信号较好的恢复,据此可检测Ag+。该方法简便,避免了ssDNA一端标记荧光基团另一端标记猝灭基团的较为昂贵的标记费,对Ag+的检测下限为0.6nmol/L,可应用于实际水样中的检测。     

Design and fabrication of a new miniaturized capacitive accelerometer

A novel mercury-based capacitive accelerometer has been designed and fabricated. The accelerometer features a highly symmetrical cubic structure and capacitive coupling of the high-frequency input voltage, which uses a mercury drop for spring material and flexible interconnection layer between the capacitor plates. The device is mounted on a standard IC package with dimensions of 5 mm × 5 mm × 5 mm. The structure, working principle, fabrication, and mathematical model of the accelerometer are presented. Since the accelerometer uses a mercury drop as its sensitive electrode instead of a solid, which is commonly used in traditional accelerometers, the conflict between the requirements of high shock and high sensitivity is solved. The measurement results show a sensitivity of 0.2 mV (m s⁻²)⁻¹ with a corresponding resolution of 0.01 ms⁻², off-axis sensitivity of <5% and good linearity in the output voltage for accelerations up to at least 10 m s⁻².     

ANN modeling of a smart MEMS-based capacitive humidity sensor

This paper presents a design of a smart humidity sensor. First we begin by the modeling of a Capacitive MEMS-based humidity sensor. Using neuronal networks and Matlab environment to accurately express the non-linearity, the hysteresis effect and the cross sensitivity of the output humidity sensor used. We have done the training to create an analytical model CHS “Capacitive Humidity Sensor”. Because our sensor is a capacitive type, the obtained model on PSPICE reflects the humidity variation by a capacity variation, which is a passive magnitude; it requires a conversion to an active magnitude, why we realize a conversion capacity/voltage using a switched capacitor circuit SCC. In a second step a linearization, by Matlab program, is applied to CHS response whose goal is to create a database for an element of correction “CORRECTOR”. After that we use the bias matrix and the weights matrix obtained by training to establish the CHS model and the CORRECTOR model on PSPICE simulator, where the output of the first is identical to the output of the CHS and the last correct its nonlinear response, and eliminate its hysteresis effect and cross sensitivity. The three blocks; CHS model, CORRECTOR model and the capacity/voltage converter, represent the smart sensor.     

高精度电容式MEMS加速度计系统设计

在传统Σ-Δ架构基础上,引入了低精度高速模/数转换器(ADC),将前置放大器输出的模拟电压信号转换为数字信号,有利于简化电容式微电子机械系统(MEMS)加速度计系统模拟接口电路设计.在嵌入ADC的MEMS加速度系统中,采用过采样平均数字算法对信号进行估计,有效降低系统对前置放大器噪声性能的需求,利于实现低功耗和高精度的设计目标.仿真结果表明:与未采用过采样平均技术相比,当前置放大器输出等效噪声大于1μV/Hz时,系统的信噪比(SNR)提高了约10dB.     

Concurrent visualization in a production supercomputing environment

We describe a concurrent visualization pipeline designed for operation in a production supercomputing environment. The facility was initially developed on the NASA Ames "Columbia" supercomputer for a massively parallel forecast model (GEOS4). During the 2005 Atlantic hurricane season, GEOS4 was run 4 times a day under tight time constraints so that its output could be included in an ensemble prediction that was made available to forecasters at the National Hurricane Center. Given this time-critical context, we designed a configurable concurrent pipeline to visualize multiple global fields without significantly affecting the runtime model performance or reliability. We use MPEG compression of the accruing images to facilitate live low-bandwidth distribution of multiple visualization streams to remote sites. We also describe the use of our concurrent visualization framework with a global ocean circulation model, which provides a 864-fold increase in the temporal resolution of practically achievable animations. In both the atmospheric and oceanic circulation models, the application scientists gained new insights into their model dynamics, due to the high temporal resolution animations attainable.     

一种可视化的定位系统设计

基于GPS技术,以太阳能进行辅助供电、以STC12C5A60S2单片机为控制器的核心、GPS接收模块U-blox NEO-6M接收GPS信号、GSM/GPRS模块接发数据、具有JPEG压缩功能的CMOS图像传感器OV2640进行图像处理,成功研制出成本低廉、测量精度较高、具有可视化功能的定位系统。测试表明,系统能准确显示监控对象的位置及图片信息,相对位置误差小于2 m。该技术可以应用于视觉导航、车辆防盗、老人/小孩定位、犯人管理等领域。     

新型单片电容式传感器的研制

介绍研制成功的一种单片电容式传感器的测头工作原理 ,提出了一种用于非金属薄膜测厚的单片电容式检测技术。通过对测量准确度的分析和实际应用 ,证明效果良好 ,在纸张、塑料薄膜、工业胶片及纬编织物等非金属薄膜测厚方面有很大的实用价值。     

Design and optimization of a MEMS electret-based capacitive energy scavenger

In this paper, a method for the design and optimization of an electret-based vibration-to-electric microconverter is presented, using a nonlinear dynamical model of the device. The dynamics of the converter is analyzed in detail, showing the importance of properly accounting for the nonlinearity in the optimization process. A procedure to determine a set of optimization parameters is finally presented.