Nothing Special   »   [go: up one dir, main page]

Next Issue
Volume 2, September
Previous Issue
Volume 2, March
You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.
 
 

Micromachines, Volume 2, Issue 2 (June 2011) – 12 articles , Pages 82-318

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
357 KiB  
Article
Infrared Ellipsometric Study of Hydrogen-Bonded Long-Chain Thiolates on Gold: Towards Resolving Structural Details
by Dimiter Tsankov, Irena Philipova, Kalina Kostova and Karsten Hinrichs
Micromachines 2011, 2(2), 306-318; https://doi.org/10.3390/mi2020306 - 22 Jun 2011
Cited by 1 | Viewed by 8159
Abstract
A set of newly synthesized aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OH; 3,5-di-OH) are self-assembled on Au(111) substrate. Self assembled monolayers (SAMs) formed by these molecules are studied by ellipsometry from infrared to visible spectral range. Best fit calculations based on the [...] Read more.
A set of newly synthesized aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OH; 3,5-di-OH) are self-assembled on Au(111) substrate. Self assembled monolayers (SAMs) formed by these molecules are studied by ellipsometry from infrared to visible spectral range. Best fit calculations based on the three-phase optical model are employed in order to determine the average tilt angle of the hydrocarbon chains. The data revealed that the SAMs reside in a crystalline-like environment as the long methylene chains predominantly exist in all-trans conformation. The calculated tilt angle of the hydrocarbon chain is decreased by approximately 12° in comparison with the one for the correspondent long-chain n-alkyl thiols. Strong hydrogen bonded networks were detected between the amide proton and the carbonyl oxygen as well as between hydroxyl groups in the end aryl substituents. The transition dipole moments of the C=O, N-H and O-H modes are oriented almost parallel to the gold surface. Full article
(This article belongs to the Special Issue Self-Assembly)
Show Figures


<p>(Top) IR <span class="html-italic">tan ψ</span> ellipsometric spectrum of <b>5a</b> monolayer on Au(111), measured at 70° angle of incidence and spectral resolution of 4 cm<sup>−1</sup>. (Bottom) IR absorption spectrum of the bulk compound in KBr. All IR absorption spectra were measured at sample concentration 1 mg:300 mg KBr.</p>
Full article ">
<p>IR <span class="html-italic">tan ψ</span> ellipsometric spectrum (top) of <b>5b</b> SAM on Au(111). The angle of incidence was 70° and the spectral resolution 4 cm<sup>−1</sup>. (Bottom) IR absorption spectrum of the bulk compound in KBr.</p>
Full article ">
<p>Simulated (red line) and experimental (black line) fragment of the ellipsometric <span class="html-italic">tarnψ</span> spectrum (top) and <span class="html-italic">Δ</span> spectrum (bottom) of <b>5a</b>. The following quantities were used for the calculations: <span class="html-italic">n</span><sub>∞</sub> = 1.4, d = 2.85 nm. Adopting the total oscillator strength parameters as used in Reference 31 the respective oscillator strength components <span class="html-italic">F<sub>x</sub></span> and <span class="html-italic">F<sub>z</sub></span> were determined: <span class="html-italic">F<sub>x</sub></span> = 40,500 cm<sup>−2</sup> and <span class="html-italic">F<sub>z</sub></span> = 4,000 cm<sup>−2</sup> for ν<sub>s</sub>(CH<sub>2</sub>) at 2,851 cm<sup>−1</sup> and <span class="html-italic">F<sub>x</sub></span> = 66,250 cm<sup>−2</sup> and <span class="html-italic">F<sub>z</sub></span> = 9,000 cm<sup>−2</sup> for ν<sub>as</sub>(CH<sub>2</sub>) at 2,919 cm<sup>−1</sup>. A value of 17 cm<sup>−1</sup> was used for full width at half maximum FWHM (Γ<sub>i</sub>) of both bands. Subsequent substitution of these quantities in <a href="#FD2" class="html-disp-formula">Equations 2</a> and <a href="#FD3" class="html-disp-formula">3</a> yields the dielectric function and the correlated optical constants.</p>
Full article ">
<p>Schematic drawings of the orientation of molecules <b>5a</b> (left) and <b>5b</b> (right) on Au(111).</p>
Full article ">
<p>Chemical formula of the target compounds.</p>
Full article ">
<p>i: Zn/AcOH, AcCl; ii: H<sub>2</sub>N-R, EDCI, HOBt, 0.5 eq DMAP, 20°, 24 h; iii: BBr<sub>3</sub>, CH<sub>2</sub>Cl<sub>2</sub>, 20°, 24 h; (iv) NaOMe, MeOH, 10% HCl.</p>
Full article ">
476 KiB  
Communication
Jitterbot: A Mobile Millirobot Using Vibration Actuation
by Samara Firebaugh, Jenelle Piepmeier, Elizabeth Leckie and John Burkhardt
Micromachines 2011, 2(2), 295-305; https://doi.org/10.3390/mi2020295 - 15 Jun 2011
Cited by 8 | Viewed by 8026
Abstract
Microrobotics is a rapidly growing field with promising applications in microsurgery and microassembly. A challenge in these systems is providing power and control signals to the robot. This project explores crawling robots that are powered and controlled through a global mechanical vibration field. [...] Read more.
Microrobotics is a rapidly growing field with promising applications in microsurgery and microassembly. A challenge in these systems is providing power and control signals to the robot. This project explores crawling robots that are powered and controlled through a global mechanical vibration field. Structures within the robot will cause it to respond to particular frequencies with different motion modalities. A prototype, dubbed the “jitterbot”, was cut out of a 0.75 mm sheet of steel using electric discharge machining (EDM), and has a total footprint of approximately 30 mm × 20 mm in the xy-plane. The “robot” has a tripod body (8 mm × 16 mm) with three small legs, and two suspended masses that are designed for specific resonance frequencies. The robot was tested on a plate that was vibrated vertically at frequencies ranging from 20 to 2,000 Hz. For particular resonant frequencies, the robot moves forward and turns in either a clockwise or counterclockwise direction. Finite element modeling confirms that the mechanism for motion is a rocking mode that is influenced by two arms that are suspended mass springs tuned to different frequencies. This lays the groundwork for further miniaturization. Full article
(This article belongs to the Special Issue Microrobots)
Show Figures


<p>Top view of a Jitterbot.</p>
Full article ">
<p>Side view of model in COMSOL illustrating the larger front leg and shorter rear legs. The main body of the robot is angled upward from the ground. The front leg angle, <span class="html-italic">θ</span>, is shown in the figure.</p>
Full article ">
<p>Illustration of boundary conditions for COMSOL simulation.</p>
Full article ">
<p>Eigenmodes as simulated in COMSOL for the jitterbot.</p>
Full article ">
<p>Test setup for Jitterbot.</p>
Full article ">
<p>Still shots illustrating the robot turning clockwise at 810 Hz.</p>
Full article ">
<p>Still shots illustrating the robot turning counter-clockwise at 1,090 Hz.</p>
Full article ">
<p>Sample trajectory of robot at 686 Hz.</p>
Full article ">
<p>Sample trajectory of robot at 1,090 Hz.</p>
Full article ">
725 KiB  
Review
Recent Progress in Piezoelectric Conversion and Energy Harvesting Using Nonlinear Electronic Interfaces and Issues in Small Scale Implementation
by Daniel Guyomar and Mickaël Lallart
Micromachines 2011, 2(2), 274-294; https://doi.org/10.3390/mi2020274 - 3 Jun 2011
Cited by 215 | Viewed by 16493
Abstract
This paper aims at providing an up-to-date review of nonlinear electronic interfaces for energy harvesting from mechanical vibrations using piezoelectric coupling. The basic principles and the direct application to energy harvesting of nonlinear treatment of the output voltage of the transducers for conversion [...] Read more.
This paper aims at providing an up-to-date review of nonlinear electronic interfaces for energy harvesting from mechanical vibrations using piezoelectric coupling. The basic principles and the direct application to energy harvesting of nonlinear treatment of the output voltage of the transducers for conversion enhancement will be recalled, and extensions of this approach presented. Latest advances in this field will be exposed, such as the use of intermediate energy tanks for decoupling or initial energy injection for conversion magnification. A comparative analysis of each of these techniques will be performed, highlighting the advantages and drawbacks of the methods, in terms of efficiency, performance under several excitation conditions, complexity of implementation and so on. Finally, a special focus of their implementation in the case of low voltage output transducers (as in the case of microsystems) will be presented. Full article
(This article belongs to the Special Issue Energy Harvesting)
Show Figures


<p>General schematic of a vibration energy harvester.</p>
Full article ">
<p>Electromechanically coupled spring-mass-damper system.</p>
Full article ">
<p>(<b>a</b>) Waveforms of the displacement, speed and piezovoltage induced by the switching process on zero speed values (the bottom figure shows how the voltage in the nonlinear processing may be decomposed into a voltage proportional to the displacement and a piecewise constant voltage that is proportional to the sign of the speed and much larger than the original voltage); (<b>b</b>) Implementation of the nonlinear treatment.</p>
Full article ">
<p>Standard energy harvesting interface.</p>
Full article ">
<p>Synchronized Switch Harvesting on Inductor (SSHI): (<b>a</b>) Parallel SSHI; (<b>b</b>) Series SSHI.</p>
Full article ">
<p>Hybrid SSHI.</p>
Full article ">
<p>SSDCI.</p>
Full article ">
<p>Active energy harvesting scheme.</p>
Full article ">
<p>Synchronous Electric Charge Extraction (SECE).</p>
Full article ">
823 KiB  
Article
Optimization of Liquid DiElectroPhoresis (LDEP) Digital Microfluidic Transduction for Biomedical Applications
by Raphaël Renaudot, Vincent Agache, Bruno Daunay, Pierre Lambert, Momoko Kumemura, Yves Fouillet, Dominique Collard and Hiroyuki Fujita
Micromachines 2011, 2(2), 258-273; https://doi.org/10.3390/mi2020258 - 3 Jun 2011
Cited by 30 | Viewed by 10228
Abstract
Digital microfluidic has recently been under intensive study, as an effective method to carry out liquid manipulation in Lab-On-a-Chip (LOC) systems. Among droplet actuation forces, ElectroWetting on Dielectric (EWOD) and Liquid DiElectroPhoresis (LDEP) are powerful tools, used in many LOC platforms. Such digital [...] Read more.
Digital microfluidic has recently been under intensive study, as an effective method to carry out liquid manipulation in Lab-On-a-Chip (LOC) systems. Among droplet actuation forces, ElectroWetting on Dielectric (EWOD) and Liquid DiElectroPhoresis (LDEP) are powerful tools, used in many LOC platforms. Such digital microfluidic transductions do not require integration of complex mechanical components such as pumps and valves to perform the fluidic operations. However, although LDEP has been proved to be efficient to carry and manipulate biological components in insulating liquids, this microfluidic transduction requires several hundreds of volts at relatively high frequencies (kHz to MHz). With the purpose to develop integrated microsystems µ-TAS (Micro Total Analysis System) or Point of Care systems, the goal here is to reduce such high actuation voltage, the power consumption, though using standard dielectric materials. This paper gives key rules to determine the best tradeoff between liquid manipulation efficiency, low-power consumption and robustness of microsystems using LDEP actuation. This study leans on an electromechanical model to describe liquid manipulation that is applied to an experimental setup, and provides precise quantification of both actuation voltage Vth and frequency fc thresholds between EWOD and LDEP regimes. In particular, several parameters will be investigated to quantify Vth and fc, such as the influence of the chip materials, the electrodes size and the device configurations. Compared to current studies in the field, significant reduction of both Vth and fc is achieved by optimization of the aforementioned parameters. Full article
(This article belongs to the Special Issue Biomedical Microdevices)
Show Figures


<p>Schematics of a typical device used for LDEP actuation in <b>(a)</b> single-plate open microfluidic device configuration and <b>(b)</b> a parallel-plate closed microfluidic device configuration. The parameters of all the layers are summarized in <a href="#t1-micromachines-02-00258" class="html-table">Table 1</a>. The layer in green refers to a dielectric layer; the layer in pink refers to a hydrophobic layer. The liquid is represented in blue and the wafer in grey. The electrodes are patterned in orange.</p>
Full article ">
<p><b>(a)</b> Equivalent electric circuit of a LDEP actuation device. <b>(b)</b> Scheme describing liquid actuation using LDEP and forces acting on the protrusion.</p>
Full article ">
<p>Optical micrograph of a 1,400 μm long liquid protrusion along electrodes without any bumps (<span class="html-italic">w</span> = <span class="html-italic">5 μm</span>, <span class="html-italic">g</span> = <span class="html-italic">6 μm</span>, <span class="html-italic">f</span> = <span class="html-italic">100 kHz</span>).</p>
Full article ">
<p><b>(a)</b> Threshold voltage actuation as a function of the electrode width <span class="html-italic">w</span> for different inter-electrode gap <span class="html-italic">g</span> Blue star labels represent the minimum of the function <span class="html-italic">V<sub>th</sub></span> = <span class="html-italic">f(w)</span> for each given inter-electrode gap. <b>(b)</b> Electrode width <span class="html-italic">w</span> as a function of the gap <span class="html-italic">g</span>,corresponding to the minimum threshold actuation voltages <span class="html-italic">V<sub>th</sub></span>. (Both figures are obtained with <span class="html-italic">f</span> = <span class="html-italic">10f<sub>c</sub></span>, <span class="html-italic">σ<sub>liq</sub></span> = <span class="html-italic">6</span> × <span class="html-italic">10<sup>−6</sup></span> <span class="html-italic">S m<sup>−1</sup></span>, <span class="html-italic">ε<sub>liq</sub></span> = <span class="html-italic">80</span>, <span class="html-italic">d</span> = <span class="html-italic">100 nm</span> SiN (<span class="html-italic">ε<sub>SiN</sub></span> ≈ 6.3) and <span class="html-italic">h</span> = <span class="html-italic">100 nm</span> SiOC (<span class="html-italic">ε<sub>SiOC</sub></span> ≈ 2.75).</p>
Full article ">
<p>Threshold voltage <span class="html-italic">V<sub>th</sub></span> as a function of the electrode width <span class="html-italic">w</span> and the inter-electrode gap <span class="html-italic">g.</span> Solid line curves and circle labels represent the numerical results and experimental data respectively. The actuated liquid corresponds to DI water (<span class="html-italic">σ<sub>liq</sub></span> = <span class="html-italic">6</span> × <span class="html-italic">10<sup>−5</sup></span> <span class="html-italic">S m<sup>−1</sup></span>, <span class="html-italic">ε</span><sub>liq</sub> = <span class="html-italic">80</span>) and chip materials are described in Section 3.</p>
Full article ">
<p><b>(a)</b> Graphical illustration of <a href="#FD7" class="html-disp-formula">equation (16)</a>: threshold actuation voltage V<sub>th</sub> as a function of <span class="html-italic">α</span> (ultra-pure water: <span class="html-italic">σ<sub>liq</sub></span> = <span class="html-italic">6</span> × <span class="html-italic">10<sup>−6</sup></span> <span class="html-italic">S m<sup>−1</sup></span>, <span class="html-italic">ε<sub>liq</sub></span> =<span class="html-italic">80</span>, <span class="html-italic">w/g</span> = 20/10 <span class="html-italic">μm</span>, <span class="html-italic">f</span> = <span class="html-italic">10 f<sub>c</sub></span>); <b>(b)</b> (<span class="html-italic">V<sub>th</sub>;f<sub>c</sub></span>) diagram according to different stacks and materials. The relative permittivity considered for SiN, SiOC, Al<sub>2</sub>O<sub>3</sub>, HfO<sub>2</sub> and ZrO<sub>2</sub> are respectively 6.3, 2.75, 8, 12 and 25. The first four points represent a stack composed by two layers. The table summarizes the thicknesses for each layer/stack. Calculations are performed for an ultra-pure water liquid (<span class="html-italic">σ<sub>liq</sub></span> = <span class="html-italic">6</span> × <span class="html-italic">10<sup>−6</sup></span> <span class="html-italic">S m<sup>−1</sup></span>, <span class="html-italic">ε<sub>liq</sub></span> = <span class="html-italic">80</span>) with. <span class="html-italic">w/g</span> = 20/10 <span class="html-italic">μm</span>.</p>
Full article ">
<p>Diagram (dSiN ; hSiOC) illustrating the breakdown area given the dielectric breakdown electric field of the hydrophobic SiOC layer. The electric field breakdown considered for the SiOC is 2 MV cm<sup>−1</sup>. ESiOC represents the electric field in the SiOC layer. Calculations are carried out at V = Vth and f = 1 kHz for an ultra-pure water liquid finger actuation with w = 20 μm and g = 10 μm.</p>
Full article ">
<p><b>(a)</b> Graph illustrating two ratios as a function of inter-electrode gap comparing both devices configuration: the single-plate open microfluidic device and the parallel-plate closed microfluidic device. Blue curve represents the ratio of liquid capacitance between the two microfluidic configurations. Red curve represents the ratio of threshold voltage actuation between the two microfluidic configurations. Calculations are carried out at <span class="html-italic">f</span> = <span class="html-italic">10f<sub>c</sub></span> for an ultra pure water (<span class="html-italic">σ<sub>liq</sub></span> = <span class="html-italic">6</span> × <span class="html-italic">10<sup>−5</sup></span> <span class="html-italic">S m<sup>−1</sup></span>, <span class="html-italic">ε<sub>liq</sub></span> = <span class="html-italic">80</span>) liquid finger actuation with a liquid cross-section area <span class="html-italic">S<sub>liq</sub></span> =<span class="html-italic">10<sup>4</sup></span> μm<sup>2</sup> and with 100 nm thick SiN layer and 100 nm thick SiOC layer. <b>(b)</b> Graph illustrating the threshold voltage actuation ratio between the two-plates and the single-plate device as a function of the inter-electrode gap for several liquid cross-sections considered. Calculations are made at <span class="html-italic">f</span> = <span class="html-italic">10f<sub>c</sub></span> for an ultra pure water liquid finger actuation and with 100 nm thick SiN and 100 nm thick SiOC.</p>
Full article ">
3857 KiB  
Review
Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures
by Guy M. Burrow and Thomas K. Gaylord
Micromachines 2011, 2(2), 221-257; https://doi.org/10.3390/mi2020221 - 3 Jun 2011
Cited by 96 | Viewed by 23403
Abstract
Research in recent years has greatly advanced the understanding and capabilities of multi-beam interference (MBI). With this technology it is now possible to generate a wide range of one-, two-, and three-dimensional periodic optical-intensity distributions at the micro- and nano-scale over a large [...] Read more.
Research in recent years has greatly advanced the understanding and capabilities of multi-beam interference (MBI). With this technology it is now possible to generate a wide range of one-, two-, and three-dimensional periodic optical-intensity distributions at the micro- and nano-scale over a large length/area/volume. These patterns may be used directly or recorded in photo-sensitive materials using multi-beam interference lithography (MBIL) to accomplish subwavelength patterning. Advances in MBI and MBIL and a very wide range of applications areas including nano-electronics, photonic crystals, metamaterials, subwavelength structures, optical trapping, and biomedical structures are reviewed and put into a unified perspective. Full article
(This article belongs to the Special Issue Nano-photonic Devices)
Show Figures


<p>Two-beam interference. Interference fringes at the <span class="html-italic">x-y</span> plane with a periodicity of Λ are formed by two linearly-polarized, monochromatic, plane waves. In this example, <b>k</b><span class="html-italic"><sub>1</sub></span> and <b>k</b><span class="html-italic"><sub>2</sub></span> are contained in the <span class="html-italic">y-z</span> plane at an angle <span class="html-italic">θ</span> with respect to the <span class="html-italic">z</span> axis.</p>
Full article ">
<p>Three-beam interference. <b>(a)</b> Three beams defined by <b>k</b><span class="html-italic"><sub>1</sub></span>, <b>k</b><span class="html-italic"><sub>2</sub></span>, and <b>k</b><span class="html-italic"><sub>3</sub></span> interfere at the <span class="html-italic">x-y</span> plane at a common angle of incidence <span class="html-italic">θ</span> with respect to the <span class="html-italic">z</span> axis. The beam pairs defined by <b>(b) k</b><span class="html-italic"><sub>1</sub></span> and <b>k</b><span class="html-italic"><sub>2</sub></span>, <b>(c) k</b><span class="html-italic"><sub>1</sub></span> and <b>k</b><span class="html-italic"><sub>3</sub></span>, and <b>(d) k</b><span class="html-italic"><sub>2</sub></span> and <b>k</b><span class="html-italic"><sub>3</sub></span> form three distinct 1D-interference fringe patterns. <b>(e)</b> The fringes patterns of <b>k</b><span class="html-italic"><sub>1</sub></span> and <b>k</b><span class="html-italic"><sub>2</sub></span> and <b>k</b><span class="html-italic"><sub>1</sub></span> and <b>k</b><span class="html-italic"><sub>3</sub></span> combine to form a square lattice <span class="html-italic">with p4m</span> plane group symmetry. <b>(f)</b> The fringe pattern of <b>k</b><span class="html-italic"><sub>2</sub></span> and <b>k</b><span class="html-italic"><sub>3</sub></span> combine with the other two fringe patterns to form a square lattice with <span class="html-italic">cmm</span> plane group symmetry. The lattice constant <span class="html-italic">a</span> for the resulting pattern is directly proportional to the common beam wavelength <span class="html-italic">λ</span> and inversely proportional to the sine of <span class="html-italic">θ</span>.</p>
Full article ">
<p>MBI pattern examples. <b>(a)</b> 2D hexagonal lattice with <span class="html-italic">p6m</span> plane group symmetry. <b>(b)</b> 3D body-centered-cubic lattice (reproduced with permission from [<a href="#b28-micromachines-02-00221" class="html-bibr">28</a>]). <b>(c)</b> 2D honey-comb structure (reproduced with permission from [<a href="#b18-micromachines-02-00221" class="html-bibr">18</a>], Copyright 2006, American Institute of Physics).</p>
Full article ">
<p>Amplitude-splitting MBI configurations. <b>(a)</b> Two-beam configuration used to record a subwavelength polarization-dependent reflection grating (edited with permission from [<a href="#b98-micromachines-02-00221" class="html-bibr">98</a>]). <b>(b)</b> Three-beam MBIL configuration for single-exposure 2D patterning with individual control of beam amplitudes and polarization (edited with permission from [<a href="#b99-micromachines-02-00221" class="html-bibr">99</a>], Copyright 2011, American Institute of Physics). <b>(c)</b> Five-beam MBIL configuration for single-exposure patterning with a diffractive beam splitter (DBS), confocal lens system (edited with permission from [<a href="#b88-micromachines-02-00221" class="html-bibr">88</a>], Copyright 2001, American Institute of Physics). <b>(d)</b> Cascaded phase gratings to implement achromatic interference lithography (edited with permission from [<a href="#b92-micromachines-02-00221" class="html-bibr">92</a>], Copyright 1995, American Vacuum Society).</p>
Full article ">
<p>Wavefront-splitting MBI configurations. <b>(a)</b> Lloyd's mirror configuration reflects a portion of the incident beam onto the transmitted beam at the sample. <b>(b)</b> A prism is used to divide and refract different portions of an incident collimated beam to produce four-beam umbrella interference (edited with permission from [<a href="#b136-micromachines-02-00221" class="html-bibr">136</a>], Copyright 2005, American Institute of Physics). <b>(c)</b> A diffractive photo-mask diffracts portions of the incident expanded beam such that the first order diffracted beams intersect and interfere at the sample plane (edited with permission from [<a href="#b112-micromachines-02-00221" class="html-bibr">112</a>], Copyright 2001, American Institute of Physics). <b>(d)</b> A 1D phase mask diffracts the incident beam into +1, 0, and −1 diffracted orders to create a near-field interference pattern (edited with permission from [<a href="#b123-micromachines-02-00221" class="html-bibr">123</a>]). <b>(e)</b> A double-iris amplitude mask defines two MBIL beams from a single collimated source for multiple two-beam interference patterning (edited with permission from [<a href="#b133-micromachines-02-00221" class="html-bibr">133</a>]).</p>
Full article ">
<p>Multi-beam interference lithography. <b>(a)</b> Scanning electron microscope image of the combined use of MBIL and projection lithography techniques. Here, 45 nm grid lines were produced via two-beam interference lithography. Next, the higher spatial frequency modulating pattern was recorded via projection lithography (Copyright 2004, Reprinted with permission of Cambridge University Press [<a href="#b2-micromachines-02-00221" class="html-bibr">2</a>]). <b>(b)</b> A complex composite pattern is created by two MBIL exposures and two projection lithography trim exposures (edited with permission from [<a href="#b5-micromachines-02-00221" class="html-bibr">5</a>]).</p>
Full article ">
<p>Photonic crystals (PC). <b>(a)</b> 3D face-centered-cubic PC structure created by four-beam MBIL. Inset <b>A</b> shows a scanning electron microscope image of the bottom surface of the PC, while <b>B</b> depicts the reconstructed 3D surface (Reprinted by permission from Macmillian Publishers Ltd: [<a href="#b157-micromachines-02-00221" class="html-bibr">157</a>], Copyright 2000). <b>(b)</b> PC waveguide created by electron-beam lithography in a 2D hexagonal lattice formed by UV MBIL (edited with permission from [<a href="#b174-micromachines-02-00221" class="html-bibr">174</a>]). <b>(c)</b> Schematic view of an air-bridge type PC band edge laser with scanning electron microscope images of the square lattice PC structure fabricated using MBIL (edited with permission from [<a href="#b205-micromachines-02-00221" class="html-bibr">205</a>], Copyright 2005, American Institute of Physics).</p>
Full article ">
<p>Metamaterial examples. <b>(a)</b> Scanning electron microscope view of a “magnetic atom” defined by a three-beam-generating MBIL prism, with an oblique-incidence view of layered Au (golden), MgF<sub>2</sub> (blue), and Au (edited with permission from [<a href="#b222-micromachines-02-00221" class="html-bibr">222</a>]). <b>(b)</b> Scanning electron microscope view of double-split ring resonator array metamaterial fabricated via phase-modulated six-beam MBIL (edited with permission from [<a href="#b224-micromachines-02-00221" class="html-bibr">224</a>]).</p>
Full article ">
<p>Subwavelength optical structures. <b>(a)</b> Synthesized-index anti-reflective Si post array defined by multi-exposure MBIL (edited from [<a href="#b231-micromachines-02-00221" class="html-bibr">231</a>], Copyright 2010, with permission from Elsevier). <b>(b)</b> Form-birefringent polarization grating retarder fabricated via two-beam interference (edited with permission from [<a href="#b98-micromachines-02-00221" class="html-bibr">98</a>]).</p>
Full article ">
6745 KiB  
Review
Microvalves and Micropumps for BioMEMS
by Anthony K. Au, Hoyin Lai, Ben R. Utela and Albert Folch
Micromachines 2011, 2(2), 179-220; https://doi.org/10.3390/mi2020179 - 24 May 2011
Cited by 291 | Viewed by 35218
Abstract
This review presents an extensive overview of a large number of microvalve and micropump designs with great variability in performance and operation. The performance of a given design varies greatly depending on the particular assembly procedure and there is no standardized performance test [...] Read more.
This review presents an extensive overview of a large number of microvalve and micropump designs with great variability in performance and operation. The performance of a given design varies greatly depending on the particular assembly procedure and there is no standardized performance test against which all microvalves and micropumps can be compared. We present the designs with a historical perspective and provide insight into their advantages and limitations for biomedical uses. Full article
(This article belongs to the Special Issue Micromixers)
Show Figures


<p>(<b>left</b>) Schematic of electrokinetic valving microchip. (<b>right</b>) Bright-field image of valve (<b>a</b>) and fluorescence images of (<b>b</b>) loading, (<b>c</b>) dispensing, and (<b>d</b>) analysis modes. Figure contributed by J. Michael Ramsey. Reprinted with permission from Jacobson <span class="html-italic">et al.</span> [<a href="#b16-micromachines-02-00179" class="html-bibr">16</a>]. Copyright 1999 American Chemical Society.</p>
Full article ">
<p>SEM images of “Flow Field-Effect Transistor” channel junction and side channel cross section (<b>a</b>), and illustrations of EOF development (<b>b</b>), enhancing field influence (<b>c</b>), and inverting field influence (<b>d</b>) (from Schasfoort <span class="html-italic">et al.</span> [<a href="#b17-micromachines-02-00179" class="html-bibr">17</a>]). Figure contributed by Albert van den Berg.</p>
Full article ">
<p>(<b>a</b>) Micrograph and schematic of a PDMS pneumatic microvalve, (<b>b</b>) 3D diagram of an elastomeric peristaltic pump (from Unger <span class="html-italic">et al.</span> [<a href="#b9-micromachines-02-00179" class="html-bibr">9</a>]), and (<b>c</b>) schematic of a microfluidic multiplexer (from Thorsen <span class="html-italic">et al.</span> [<a href="#b30-micromachines-02-00179" class="html-bibr">30</a>]). Figure contributed by Stephen Quake.</p>
Full article ">
<p>3D schematics (<b>left</b>) and micrographs (<b>right</b>) of closed (<b>a</b>) and open (<b>b</b>) plunger microvalve (from Baek <span class="html-italic">et al.</span> [<a href="#b39-micromachines-02-00179" class="html-bibr">39</a>]). Reprinted with permission from IOP Publishing Ltd.</p>
Full article ">
<p>(<b>a</b>) Schematic of microfluidic sorter using PDMS microvalves implemented in the sidewall, and (<b>b</b>) demonstration of sorting action (from Sundararajan <span class="html-italic">et al.</span> [<a href="#b5-micromachines-02-00179" class="html-bibr">5</a>]). Figure reproduced with permission from The Royal Society of Chemistry.</p>
Full article ">
<p>Micrographs of three “doormat” microvalves in closed (<b>A</b>) and open (<b>B</b>) states (from Hosokawa <span class="html-italic">et al.</span> [<a href="#b7-micromachines-02-00179" class="html-bibr">7</a>]). Reprinted with permission from IOP Publishing Ltd.</p>
Full article ">
<p>Operation of PDMS “doormat” microvalves (from Li <span class="html-italic">et al.</span> [<a href="#b44-micromachines-02-00179" class="html-bibr">44</a>]). Figure contributed by Nianzhen Li and Greg Boggy. Copyright Wiley-VCH Verlag GmbH &amp; Co. KGaA. Reproduced with permission.</p>
Full article ">
<p>Metering of nanoliter volumes with PDMS “doormat” microvalves (from Li <span class="html-italic">et al.</span> [<a href="#b44-micromachines-02-00179" class="html-bibr">44</a>]). Figure contributed by Greg Boggy. Copyright Wiley-VCH Verlag GmbH &amp; Co. KGaA. Reproduced with permission.</p>
Full article ">
<p>Schematics of PDMS “curtain” microvalve fabrication (<b>a</b>), top view (<b>b</b>), and side view (<b>c</b>), and operation of the microstructured membrane (<b>d</b>–<b>e</b>) (from Irimia <span class="html-italic">et al.</span> [<a href="#b49-micromachines-02-00179" class="html-bibr">49</a>]). Figure contributed by Mehmet Toner. Figure reproduced with permission from The Royal Society of Chemistry.</p>
Full article ">
408 KiB  
Article
Effect of the Detector Width and Gas Pressure on the Frequency Response of a Micromachined Thermal Accelerometer
by Alexandra Garraud, Philippe Combette, Johann Courteaud and Alain Giani
Micromachines 2011, 2(2), 167-178; https://doi.org/10.3390/mi2020167 - 23 May 2011
Cited by 10 | Viewed by 7333
Abstract
In the present work, the design and the environmental conditions of a micromachined thermal accelerometer, based on convection effect, are discussed and studied in order to understand the behavior of the frequency response evolution of the sensor. It has been theoretically and experimentally [...] Read more.
In the present work, the design and the environmental conditions of a micromachined thermal accelerometer, based on convection effect, are discussed and studied in order to understand the behavior of the frequency response evolution of the sensor. It has been theoretically and experimentally studied with different detector widths, pressure and gas nature. Although this type of sensor has already been intensively examined, little information concerning the frequency response modeling is currently available and very few experimental results about the frequency response are reported in the literature. In some particular conditions, our measurements show a cut-off frequency at −3 dB greater than 200 Hz. By using simple cylindrical and planar models of the thermal accelerometer and an equivalent electrical circuit, a good agreement with the experimental results has been demonstrated. Full article
Show Figures


<p>Temperature profile with and without acceleration.</p>
Full article ">
<p>SEM images of the sensor: Global view and view of different detector widths, on top. Cavity scheme, underneath.</p>
Full article ">
<p>Cylindrical model shape.</p>
Full article ">
<p>Planar model shape.</p>
Full article ">
<p>Sensor bandwidth at −3 dB <span class="html-italic">vs.</span> thermal gas diffusivity, for different detector widths.</p>
Full article ">
<p>Experimental thermal sensitivity <span class="html-italic">vs.</span> detector width.</p>
Full article ">
<p>Experimental sensor bandwidth, experimental detector bandwidth (confirmed by the electrical model) and theoretical frequency response of gas <span class="html-italic">vs.</span> the detector width.</p>
Full article ">
<p>Theoretical electrical model and the experimental response of the thermal accelerometer for a detector width of 2 μm.</p>
Full article ">
<p>Detector bandwidth at −3 dB obtained with cylindrical, planar and electrical models <span class="html-italic">vs.</span> detector width.</p>
Full article ">
282 KiB  
Article
Ultrasonic Hot Embossing
by Werner Karl Schomburg, Katharina Burlage and Christof Gerhardy
Micromachines 2011, 2(2), 157-166; https://doi.org/10.3390/mi2020157 - 11 May 2011
Cited by 41 | Viewed by 10283
Abstract
Ultrasonic hot embossing is a new process for fast and low-cost production of micro systems from polymer. Investment costs are on the order of 20.000 € and cycle times are a few seconds. Microstructures are fabricated on polymer foils and can be combined [...] Read more.
Ultrasonic hot embossing is a new process for fast and low-cost production of micro systems from polymer. Investment costs are on the order of 20.000 € and cycle times are a few seconds. Microstructures are fabricated on polymer foils and can be combined to three-dimensional systems by ultrasonic welding. Full article
(This article belongs to the Special Issue Polymer MEMS)
Show Figures


<p>Schematic drawing of hot embossing: <b>(a)</b> Inserting a polymer foil into the heated tool; <b>(b)</b> Closing the tool and cooling down; <b>(c)</b> Demolding.</p>
Full article ">
<p>Schematic drawing of ultrasonic hot embossing: <b>(a)</b> Placing a stack of polymer foils on the tool; <b>(b)</b> Pressing the sonotrode onto the tool, applying ultrasound, and cooling down; <b>(c)</b> Demolding.</p>
Full article ">
<p>Left: 35 kHz ultrasonic welding machine; Right: Sonotrode, polymer foils, and tool.</p>
Full article ">
<p>Left: LIGA tool from nickel; Right: Microstructure embossed from that tool [<a href="#b9-micromachines-02-00157" class="html-bibr">9</a>].</p>
Full article ">
<p>Scanning electron micrograph (SEM) of the break through a micro mixer [<a href="#b9-micromachines-02-00157" class="html-bibr">9</a>].</p>
Full article ">
<p>From left to right: Schematic drawing of the micro pump (not to scale), photo, and characteristic curve when driven at 12.5 Hz.</p>
Full article ">
<p><b>(a)</b> One layer of micro grooves in PVDF. <b>(b)</b> Cut trough the channels with energy directors on top of the walls. <b>(c)</b> Cut through a heat exchanger with 3 channel layers welded together. <b>(d)</b> Complete heat exchanger. <b>(e)</b> Schematic drawing of the principle.</p>
Full article ">
<p><b>(a)</b> Wire enclosed between two polymer foils locally joined by ultrasonic welding; <b>(b)</b> Electronic circuit of the anemometric flow sensor; <b>(c)</b> Photo of the flow sensor.</p>
Full article ">
<p><b>(a)</b> Protruding structure on the tool with metal, adhesion, and substrate foils; <b>(b)</b> Cut through an aluminum conductor path on a PP foil; <b>(c)</b> SMD resistor embossed into PVDF and connected to copper conductor paths.</p>
Full article ">
208 KiB  
Article
Focusing Light with Curved Guided-Mode Resonance Reflectors
by Mingyu Lu, Huiqing Zhai and Robert Magnusson
Micromachines 2011, 2(2), 150-156; https://doi.org/10.3390/mi2020150 - 28 Apr 2011
Cited by 8 | Viewed by 7188
Abstract
Employing numerical simulations, we investigate the possibility of using curved guided-mode resonance (GMR) elements to focus light in reflection. We treat GMR reflectors with a parabolic shape and show that they are capable of focusing light effectively across wavelength bands that extend several [...] Read more.
Employing numerical simulations, we investigate the possibility of using curved guided-mode resonance (GMR) elements to focus light in reflection. We treat GMR reflectors with a parabolic shape and show that they are capable of focusing light effectively across wavelength bands that extend several hundred nanometers. The spatially infinite reflector model is simulated with a finite-element method, whereas the spatially finite reflector is treated with a finite-difference-time-domain method. The numerical results demonstrate that light intensity at the focal point is 8.6 dB stronger than the incident intensity when the GMR reflector’s size is on the order of 10 wavelengths. The results indicate potential applicability of wideband-focusing devices in electromagnetics and photonics using compact resonance elements. Full article
(This article belongs to the Special Issue Nano-photonic Devices)
Show Figures


<p>Illustration of <b>(a)</b> flat GMR reflector and <b>(b)</b> curved GMR reflector.</p>
Full article ">
<p>Numerical results for a planar GMR structure: <b>(a)</b> Geometry, <b>(b)</b> Results when <span class="html-italic">θ</span> = 0°, <b>(c)</b> Results when <span class="html-italic">θ</span> = 5°, <b>(d)</b> Results when <span class="html-italic">θ</span> = 10°.</p>
Full article ">
<p>Numerical results for a curved GMR structure: (<b>a)</b> Schematic rendition of device geometry, <b>(b)</b> Results for wavelength <span class="html-italic">λ</span> = 1.69 μm, <b>(c)</b> Results for wavelength <span class="html-italic">λ</span> = 1.76 μm, <b>(d)</b> Results for wavelength <span class="html-italic">λ</span> = 2 μm.</p>
Full article ">
1167 KiB  
Article
Mori-Tanaka Based Estimates of Effective Thermal Conductivity of Various Engineering Materials
by Jan Stránský, Jan Vorel, Jan Zeman and Michal Šejnoha
Micromachines 2011, 2(2), 129-149; https://doi.org/10.3390/mi2020129 - 15 Apr 2011
Cited by 48 | Viewed by 10522 | Correction
Abstract
The purpose of this paper is to present a simple micromechanics-based model to estimate the effective thermal conductivity of macroscopically isotropic materials of matrix-inclusion type. The methodology is based on the well-established Mori-Tanaka method for composite media reinforced with ellipsoidal inclusions, extended to [...] Read more.
The purpose of this paper is to present a simple micromechanics-based model to estimate the effective thermal conductivity of macroscopically isotropic materials of matrix-inclusion type. The methodology is based on the well-established Mori-Tanaka method for composite media reinforced with ellipsoidal inclusions, extended to account for imperfect thermal contact at the matrix-inclusion interface, random orientation of particles and particle size distribution. Using simple ensemble averaging arguments, we show that the Mori-Tanaka relations are still applicable for these complex systems, provided that the inclusion conductivity is appropriately modified. Such conclusion is supported by the verification of the model against a detailed finite-element study as well as its validation against experimental data for a wide range of engineering material systems. Full article
(This article belongs to the Special Issue Advances in Micromechanics and Microengineering)
Show Figures


<p>Examples of micro-graphs of real engineering materials taken in back scattered electrons: (<b>a</b>) Alkali-activated fly ash, (<b>b</b>) Alumino-silicate ceramics with Fe and silicium particles (dark phase), (<b>c</b>) Superspeed—alloying ingredient into crude iron for cast iron working with silicon particles (dark phase). Reproduced with permission of L. Kopecký (CTU in Prague).</p>
Full article ">
<p>(<b>a</b>) Evolution of effective thermal conductivity <span class="html-italic">χ</span><sup>H</sup> as a function of volume fraction of rubber in solid phase, (<b>b</b>) Correlation of measured and calculated values; <span class="html-italic">ρ</span> is the correlation coefficient.</p>
Full article ">
<p>Mori-Tanaka based scheme: Strategy of derivation.</p>
Full article ">
<p>Evolution of the normalized effective thermal conductivity <span class="html-italic">χ</span><sup>H</sup>/<span class="html-italic">χ</span><sup>m</sup> as a function of (<b>a</b>) phase contrast <span class="html-italic">α</span> and relative particle radius <span class="html-italic">a</span>/<span class="html-italic">a</span><sub>K</sub> (<span class="html-italic">c</span><sup>(1)</sup> = 30%) and (<b>b</b>) volume fraction <span class="html-italic">c</span><sup>(1)</sup> of copper particles, (<b>c</b>) correlation of measured and calculated values; <span class="html-italic">ρ</span> is the correlation coefficient.</p>
Full article ">
<p>(<b>a</b>) Examples of probability distribution functions of particle radii <span class="html-italic">a</span> for specimens No. 1 and 7, (<b>b</b>) evolution of effective thermal conductivity <span class="html-italic">χ</span><sup>H</sup> as a function of particle radius <span class="html-italic">a</span>, (<b>c</b>) correlation of measured and calculated values; <span class="html-italic">ρ</span> denotes the correlation coefficient.</p>
Full article ">
<p>Examples of random macroscopically isotropic microstructures: (<b>a</b>) circular cylinders (<span class="html-italic">β</span><sub>2</sub> = 1), (<b>b</b>) elliptical cylinders with aspect ratio <span class="html-italic">β</span><sub>2</sub> = 3, (<b>c</b>) elliptical cylinders with aspect ratio <span class="html-italic">β</span><sub>2</sub> = 9.</p>
Full article ">
<p>Variation of the normalized effective conductivity <span class="html-italic">χ</span><sup>H</sup>/<span class="html-italic">χ</span><sup>m</sup> for three microstructures in <a href="#f6-micromachines-02-00129" class="html-fig">Figure 6</a> with perfect interfaces, determined by periodic FEM homogenization for phase contrast (<b>a</b>) <span class="html-italic">α</span> = 3, (<b>b</b>) <span class="html-italic">α</span> = 10 and (<b>c</b>) <span class="html-italic">α</span> = 20; <span class="html-italic">β</span><sub>2</sub> denotes the inclusion aspect ratio and <span class="html-italic">c</span><sup>(1)</sup> the inclusion volume fraction.</p>
Full article ">
<p>(<b>a</b>) Evolution of correction factor <span class="html-italic">k</span><sub>corr</sub> for systems with perfect interfaces as a function of the ratio of semi-axes <span class="html-italic">β</span><sub>2</sub> and variation of normalized effective conductivity <span class="html-italic">χ</span><sup>H</sup>/<span class="html-italic">χ</span><sup>m</sup> obtained by FEM and MT with modified conductivity <math display="inline"> <semantics id="sm73"> <mrow> <msup> <mrow> <mover accent="true"> <mi>χ</mi> <mo stretchy="true">̃</mo></mover></mrow> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo></mrow></msup></mrow></semantics></math> for phase contrast (<b>b</b>) <span class="html-italic">α</span> = 3 and (<b>c</b>) <span class="html-italic">α</span> = 20.</p>
Full article ">
<p>Statistically isotropic distribution of circular cylinders with variable radius of their cross-section.</p>
Full article ">
904 KiB  
Article
FISHprep: A Novel Integrated Device for Metaphase FISH Sample Preparation
by Pranjul Shah, Indumathi Vedarethinam, Dorota Kwasny, Lars Andresen, Søren Skov, Asli Silahtaroglu, Zeynep Tümer, Maria Dimaki and Winnie E. Svendsen
Micromachines 2011, 2(2), 116-128; https://doi.org/10.3390/mi2020116 - 4 Apr 2011
Cited by 10 | Viewed by 10518
Abstract
We present a novel integrated device for preparing metaphase chromosomes spread slides (FISHprep). The quality of cytogenetic analysis from patient samples greatly relies on the efficiency of sample pre-treatment and/or slide preparation. In cytogenetic slide preparation, cell cultures are routinely used to process [...] Read more.
We present a novel integrated device for preparing metaphase chromosomes spread slides (FISHprep). The quality of cytogenetic analysis from patient samples greatly relies on the efficiency of sample pre-treatment and/or slide preparation. In cytogenetic slide preparation, cell cultures are routinely used to process samples (for culture, arrest and fixation of cells) and/or to expand limited amount of samples (in case of prenatal diagnostics). Arguably, this expansion and other sample pretreatments form the longest part of the entire diagnostic protocols spanning over 3–4 days. We present here a novel device with an integrated expansion chamber to culture, arrest and fix metaphase cells followed by a subsequent splashing protocol leading to ample metaphase chromosome spreads on a glass slide for metaphase FISH analysis. The device provides an easy, disposable, low cost, integrated solution with minimal handling for metaphase FISH slide preparation. Full article
(This article belongs to the Collection Lab-on-a-Chip)
Show Figures


<p>Exploded view of the FISHprep device top and bottom part. A polycarbonate membrane is sandwiched between the two parts to form the barrier between the culture chamber and perfusion meander.</p>
Full article ">
<p><b>(a)</b> Bonded FISHprep device <b>(b)</b> FISHprep device depicting paper clip based valving procedure.</p>
Full article ">
<p><b>(a)</b> Paper clip valve of the external U-section: Isolation of flow from culture chamber to splashing chamber <b>(b)</b> Flow through culture chamber on to the splashing chamber on opening of the paper clip valve (Leakage in the device at 500 μL/min flow rate).</p>
Full article ">
<p>FISHprep culture <b>(a)</b> Cells on Day 0 <b>(b)</b>: Cells on Day 3 (Background shows pores in the PC membrane). (Inset—Enlarged cytoplasm on Day 3).</p>
Full article ">
<p>CFSE proliferation assay results. Count of cells <span class="html-italic">vs.</span> the fluorescence intensity of CFSE stained cells analyzed by fluorescence cytometer. (Control experiments relate to negative control of cultures on FISHprep device without PHA stimulation).</p>
Full article ">
<p><b>(a)</b> (Top) Chromosome spreads prepared using the FISHprep device; <b>(b)</b> (Bottom) Chromosome spreads achieved using the manual dropping technique. Offset pictures present high magnification images.</p>
Full article ">
<p>FISH analysis on the FISHprep samples (The FISH signals indicate the presence of two X-chromosomes in the chromosome spreads and cells).</p>
Full article ">
2589 KiB  
Review
Modeling Self-Assembly Across Scales: The Unifying Perspective of Smart Minimal Particles
by Massimo Mastrangeli, Grégory Mermoud and Alcherio Martinoli
Micromachines 2011, 2(2), 82-115; https://doi.org/10.3390/mi2020082 - 31 Mar 2011
Cited by 13 | Viewed by 8889
Abstract
A wealth of current research in microengineering aims at fabricating devices of increasing complexity, notably by (self-)assembling elementary components into heterogeneous functional systems. At the same time, a large body of robotic research called swarm robotics is concerned with the design and the [...] Read more.
A wealth of current research in microengineering aims at fabricating devices of increasing complexity, notably by (self-)assembling elementary components into heterogeneous functional systems. At the same time, a large body of robotic research called swarm robotics is concerned with the design and the control of large ensembles of robots of decreasing size and complexity. This paper describes the asymptotic convergence of micro/nano electromechanical systems (M/NEMS) on one side, and swarm robotic systems on the other, toward a unifying class of systems, which we denote Smart Minimal Particles (SMPs). We define SMPs as mobile, purely reactive and physically embodied agents that compensate for their limited on-board capabilities using specifically engineered reactivity to external physical stimuli, including local energy and information scavenging. In trading off internal resources for simplicity and robustness, SMPs are still able to collectively perform non-trivial, spatio-temporally coordinated and highly scalable operations such as aggregation and self-assembly (SA). We outline the opposite converging tendencies, namely M/NEMS smarting and robotic minimalism, by reviewing each field’s literature with specific focus on self-assembling systems. Our main claim is that the SMPs can be used to develop a unifying technological and methodological framework that bridges the gap between passive M/NEMS and active, centimeter-sized robots. By proposing this unifying perspective, we hypothesize a continuum in both complexity and length scale between these two extremes. We illustrate the benefits of possible cross-fertilizations among these originally separate domains, with specific emphasis on the modeling of collective dynamics. Particularly, we argue that while most of the theoretical studies on M/NEMS SA dynamics belong so far to one of only two main frameworks—based on analytical master equations and on numerical agent-based simulations, respectively—alternative models developed in swarm robotics could be amenable to the task, and thereby provide important novel insights. Full article
(This article belongs to the Special Issue Self-Assembly)
Show Figures


<p>The convergence toward Smart Minimal Particles (SMPs).</p>
Full article ">
<p>Taxonomy of Self-Assembly.</p>
Full article ">
<p>Hosokawa's intermediate assembly products <b>(a)</b> and bi-particle reactions <b>(b)</b>.</p>
Full article ">
<p>Simulated evolution of self-assembly yield as in Hosokawa's model (from [<a href="#b28-micromachines-02-00082" class="html-bibr">28</a>]).</p>
Full article ">
<p>Mastrangeli's ABM of Zheng and Jacobs' fluidic SA process. <b>(a)</b> Zheng and Jacobs' experimental set-up (edited from [<a href="#b91-micromachines-02-00082" class="html-bibr">91</a>]); <b>(b)</b> ABM assembly space and agents.</p>
Full article ">
<p>The geometrical <span class="html-italic">matching capture cross-section</span> (MCCS) criterion for effective inter-agent collisions, <span class="html-italic">i.e.</span>, leading to assembly, as defined in Mastrangeli's ABM model.</p>
Full article ">
<p><b>(a)</b> Experimental and analytical, and <b>(b)</b> ABM simulation results for Zheng and Jacob<b>s</b>' fluidic SA process with initial populations of 100 LEDs (<span class="html-italic">l</span>) and 100 carriers (<span class="html-italic">c</span>) (analytical model: T<sub>A</sub> = 15 h, picture from [<a href="#b91-micromachines-02-00082" class="html-bibr">91</a>]; ABM: assembly space volume: 4,394 mm<sup>3</sup>; initial agents speed: 100 mm/s; statistics out of 10 realizations for each CCS value).</p>
Full article ">
<p>ABM-simulated effects of <b>(a)</b> LEDs-to<b>-</b>carrier ratio and <b>(b)</b> particle density on assembly rates (ABM parameters: 10× smaller assembly space, initial populations: 10 LEDs and 10 carriers, θ<b><sub>C</sub></b><sub>CS</sub> = 80°, initial agents velocity: 100 mm/s; statistics out of 10 realizations for each parameter value).</p>
Full article ">
<p>Simulated effects of inert dimers (resulting from assembly) on fluidic SA performance: for the out (in) case, the dimers are (not) removed from the assembly space after assembly (ABM parameters: 10× smaller assembly space; initial populations: 60 LEDs and 30 carriers, θ<sub>CCS</sub> = 80°, initial agents velocity: 100 mm/s; statistics out of 10 realizations for each case).</p>
Full article ">
Previous Issue
Next Issue
Back to TopTop