25,942 research outputs found
First Jump of Microgel: Actuation Speed Enhancement by Elastic Instability
Swelling-induced snap-buckling in a 3D micro hydrogel device, inspired by the
insect-trapping action of Venus flytrap, makes it possible to generate
astonishingly fast actuation. We demonstrate that elastic energy is effectively
stored and quickly released from the device by incorporating elastic
instability. Utilizing its rapid actuation speed, the device can even jump by
itself upon wetting.Comment: 4 pages, 3 figure
Sub- structured Lotus Surfaces Manufacturing
Sub-micro structured surfaces allow modifying the behavior of polymer films
or components. Especially in micro fluidics a lotus-like characteristic is
requested for many applications. Structure details with a high aspect ratio are
necessary to decouple the bottom and the top of the functional layer. Unlike to
stochastic methods, patterning with a LIGA-mold insert it is possible to
structure surfaces very uniformly or even with controlled variations (e.g. with
gradients). In this paper we present the process chain to realize polymer
sub-micro structures with minimum lateral feature size of 400 nm and up to 4
micrometers high.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Manipulating electronic states at oxide interfaces using focused micro X-rays from standard lab-sources
Recently, x-ray illumination, using synchrotron radiation, has been used to
manipulate defects, stimulate self-organization and to probe their structure.
Here we explore a method of defect-engineering low-dimensional systems using
focused laboratory-scale X-ray sources. We demonstrate an irreversible change
in the conducting properties of the 2-dimensional electron gas at the interface
between the complex oxide materials LaAlO3 and SrTiO3 by X-ray irradiation. The
electrical resistance is monitored during exposure as the irradiated regions
are driven into a high resistance state. Our results suggest attention shall be
paid on electronic structure modification in X-ray spectroscopic studies and
highlight large-area defect manipulation and direct device patterning as
possible new fields of application for focused laboratory X-ray sources.Comment: 12 pages, 4 figure
Surface micromachined electrostatically actuated micro peristaltic pump
An electrostatically actuated micro peristaltic pump is reported. The micro pump is entirely surface micromachined using a multilayer parylene technology. Taking advantage of the multilayer technology, the micro pump design enables the pumped fluid to be isolated from the electric field. Electrostatic actuation of the parylene membrane using both DC and AC voltages was demonstrated and applied to fluid pumping based on a 3-phase peristaltic sequence. A maximum flow rate of 1.7 nL min^–1 and an estimated pumping pressure of 1.6 kPa were achieved at 20 Hz phase frequency. A dynamic analysis was also performed with a lumped-parameter model for the peristaltic pump. The analysis results allow a quantitative understanding of the peristaltic pumping operation, and correctly predict the trends exhibited by the experimental data. The small footprint of the micro pump is well suited for large-scale integration of microfluidics. Moreover, because the same platform technology has also been used to fabricate other devices (e.g. valves, electrospray ionization nozzles, filters and flow sensors), the integration of these different devices can potentially lead to versatile and functional micro total analysis systems (µTAS)
On-a-chip microdischarge thruster arrays inspired by photonic device technology for plasma television
This study shows that the practical scaling of a hollow cathode thruster device to MEMS level should be possible albeit with significant divergence from traditional design. The main divergence is the need to operate at discharge pressures between 1-3bar to maintain emitter diameter pressure products of similar values to conventional hollow cathode devices. Without operating at these pressures emitter cavity dimensions become prohibitively large for maintenance of the hollow cathode effect and without which discharge voltage would be in the hundreds of volts as with conventional microdischarge devices. In addition this requires sufficiently constrictive orifice diameters in the 10µm – 50µm range for single cathodes or <5µm larger arrays. Operation at this pressure results in very small Debye lengths (4 -5.2pm) and leads to large reductions in effective work function (0.3 – 0.43eV) via the Schottky effect. Consequently, simple work function lowering compounds such as lanthanum hexaboride (LaB6) can be used to reduce operating temperature without the significant manufacturing complexity of producing porous impregnated thermionic emitters as with macro scale hollow cathodes, while still operating <1200°C at the emitter surface. The literature shows that LaB6 can be deposited using a variety of standard microfabrication techniques
Demystifying the Characteristics of 3D-Stacked Memories: A Case Study for Hybrid Memory Cube
Three-dimensional (3D)-stacking technology, which enables the integration of
DRAM and logic dies, offers high bandwidth and low energy consumption. This
technology also empowers new memory designs for executing tasks not
traditionally associated with memories. A practical 3D-stacked memory is Hybrid
Memory Cube (HMC), which provides significant access bandwidth and low power
consumption in a small area. Although several studies have taken advantage of
the novel architecture of HMC, its characteristics in terms of latency and
bandwidth or their correlation with temperature and power consumption have not
been fully explored. This paper is the first, to the best of our knowledge, to
characterize the thermal behavior of HMC in a real environment using the AC-510
accelerator and to identify temperature as a new limitation for this
state-of-the-art design space. Moreover, besides bandwidth studies, we
deconstruct factors that contribute to latency and reveal their sources for
high- and low-load accesses. The results of this paper demonstrates essential
behaviors and performance bottlenecks for future explorations of
packet-switched and 3D-stacked memories.Comment: EEE Catalog Number: CFP17236-USB ISBN 13: 978-1-5386-1232-
Improving the efficiency of thermoelectric generators by using solar heat concentrators
In this paper, we propose a method of improving the efficiency of thermoelectric generators (TEGs) by using a lens to concentrate heat on the heat source of a TEG. Initial experiments performed using discrete components show about 60mV increase in the amount of voltage generated when using a magnifying lens. Simulation results on the proposed TEG configuration exhibit up to 16% efficiency when the input heat flux is increased to 500 times that of the sun’s heat flux. The effects of varying the thermoelement length, width, and membrane diameter on the TEG’s performance are also characterized. Lastly, plans to fabricate the device on a SOI wafer in the future are presente
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