High‐speed serial‐kinematic SPM scanner: design and drive considerations
115
Citation
23
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract This paper describes the design of a flexure‐guided, two‐axis nanopositioner (scanner) driven by piezoelectric stack actuators. The scanner is specifically designed for high‐speed scanning probe microscopy (SPM) applications, such as atomic force microscopy (AFM). A high‐speed AFM scanner is an essential component for acquiring high‐resolution, three‐dimensional, time‐lapse images of fast processes such as the rapid movement of cells and the diffusion of DNA molecules. A two‐axis SPM scanner is proposed, where the slow and fast scanning axes are serially connected and flexure guided to minimize runout. The scanner's achievable scan range is approximately 10µm × 10µm. Finite element analysis is utilized to optimize the mechanical resonance frequencies of the scanner. Experimental results show a first major resonance in the slow and fast axis at 1.5 and 29 kHz, respectively. This paper also discusses the various tradeoffs between speed, range, electrical requirements, and scan trajectory design for high‐speed nanopositioning. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control SocietyThe objective of this study was to fabricate a self-humidifying fuel cell stack humidified with water recovered at the cathodes, composed of 10 cells with 104 cm2 cell areas, measure and simulate the performance of the stack. The model for the simulation is a three-dimensional model of the heat and mass transfer of water and gaseous reactants in fuel cell components with water cooling. The results of the stack experiments showed a maximum power of 250 W at the current density of 0.5 A/ cm2. The simulation model showed good agreement with the actual performance of the stack. A self-humidifying stack with a vapor permeating membrane showed a performance comparable to conventional stacks and it is very effective in simplifying stack systems. The numerical analysis showed that the stack performance is affected by the anode and cathode gas flows, co-flow is superior to cross-flow and that one cooing cell is necessary for two or three generating cells to maintain a fuel cell temperature below 100°C.
Cite
Citations (0)
Some data about kinematic calibration of parallel kinematic machine was analyzed and summarized,the machining error of parallel kinematic machine was explained,the kinematic calibration method was classified,some suggest on the study of kinematic calibration was put forward,and it was indicated that kinematic calibration is an effective method to improve the static accuracy of parallel kinematic machine.
Kinematic diagram
Machine tool
Cite
Citations (2)
The objective of this project is to design, fabricate and field demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first year of the project, a laboratory version of the multi-spectral scanner was designed, fabricated, and tested at EnUrga Inc. The multi-spectral scanner was also evaluated using a blind DoE study at RMOTC. The performance of the scanner was inconsistent during the blind DoE study. However, most of the leaks were outside the view of the multi-spectral scanner. Therefore, a definite evaluation of the capability of the scanner was not obtained. Despite the results, sufficient number of plumes was detected fully confirming the feasibility of the multi-spectral scanner. During the second year, the optical design of the scanner was changed to improve the sensitivity of the system. Laboratory tests show that the system can reliably detect small leaks (20 SCFH) at 30 to 50 feet. Electronic and mechanical design of the scanner to make it a self standing sensor was completed during the last six months of the project. The prototype scanner was tested with methane leaks at 15 feet and 30 feet, at a flow rate of 25 SCFH. The prototype scanner successfully detected the leaks. This concluded the project.
Cite
Citations (0)
Abstract This paper presents a comparative analysis of two kinematic structures of the support system (with supports with bilateral and unilateral constraints), which were used in an experimental model of a crane. The computational model was developed by using the ADAMS software. The impact of the kinematic structure of the support system on selected kinematic and dynamic values that were recorded during the slewing motion was analysed. It was found, among other things, that an increased number of degrees of freedom of the support system leads to multiple distortions of time characteristics of kinematic and dynamic quantities.
Kinematic diagram
Cite
Citations (7)
Cite
Citations (30)
The objective of this project is to design, fabricate and field demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first year of the project, a laboratory version of the multi-spectral scanner was designed, fabricated, and tested at En'Urga Inc. The multi-spectral scanner was also evaluated using a blind DoE study at RMOTC. The performance of the scanner was inconsistent during the blind DoE study. However, most of the leaks were outside the view of the multi-spectral scanner. Therefore, a definite evaluation of the capability of the scanner was not obtained. Despite the results, sufficient number of plumes was detected fully confirming the feasibility of the multi-spectral scanner. During the second year, a rugged prototype scanner will be developed and evaluated, both at En'Urga Inc. and any potential field sites.
Cite
Citations (0)
Kinematic diagram
Work space
Position (finance)
Cite
Citations (18)
The temperature of the proton exchange membrane fuel cell(PEMFC)stack is a key factor to influence the performance of the cell.It is necessary to build a model of PEMFC stack in order to control the temperature exactly.A approach using the method of BP neural networks to model the PEMFC stack was put forward and used to fit the experimental dates,the results was satisfying.
Cite
Citations (0)
A lightweight 200W direct methanol fuel cell (DMFC) stack is designed and fabricated to power a small scale Unmanned Aerial Vehicle (UAV). The DMFC stack consists of 33-cells in which membrane-electrode assemblies (MEAs) having an active area of 88 $cm^2$ are sandwiched with lightweight composite bipolar plates. The total stack weight is around 3.485 kg and stack performance is tested under various methanol feed concentrations. The DMFC stack delivers a maximum power of 248 W at 13.2 V and $71.3^{\circ}C$ under methanol feed concentration of 1.2 M. In addition, the voltage of individual cell in the 33-cell stack is measured at various current levels to ensure the stability of DMFC stack operations. The cell voltage distribution data exhibit the maximum cell voltage deviation of 28 mV at 15 A and hence the uniformity of cell voltages is acceptable. These results clearly demonstrate that DMFC technology becomes a potential candidate for small-scale UAV applications.
Maximum power principle
Cell voltage
Cite
Citations (2)
This paper introduces the concepts of “Kinematic Moment” and “ Kinematic inertia” to study the structure based velocity and acceleration characteristics respectively of kinematics chains in a comparative sense. Example problems are included. Keywords: Kinematic moment: Kinematic Inertia, Kinematic Chains, Velocities, Accelerations.
Moment of inertia
Cite
Citations (0)