APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

9 Feb 2009

Volume 94, Issue 6, Articles (06xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 062105 (2009); http://dx.doi.org/10.1063/1.3079078 (3 pages)

Ikai Lo, Chia-Ho Hsieh, Yu-Chi Hsu, Wen-Yuan Pang, and Ming-Chi Chou
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Ultrafast micropumping by biased alternating current electrokinetics

Meng Lian and Jie Wu

Appl. Phys. Lett. 94, 064101 (2009); http://dx.doi.org/10.1063/1.3080681 (3 pages) | Cited 11 times

Online Publication Date: 9 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper reports dramatic improvements in flow rate over conventional alternating current (ac) electrokinetic micropumps by exploiting asymmetry in electric potentials over the electrodes. A micropump consisting of a planar asymmetric electrode array was tested using ac signals with and without a direct current (dc) bias. All experiments were done at 100 kHz Vac. The pumping velocity is much faster with a dc voltage, in some cases by an order of magnitude, reaching a linear velocity of up to 2.5 mm/s with only 5.4 Vrms. The discovery presents an exciting opportunity for microfluidics. Future improvement can be anticipated with additional optimization.
Show PACS
47.85.Np Fluidics
47.65.-d Magnetohydrodynamics and electrohydrodynamics
47.61.Fg Flows in micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS)
47.60.Dx Flows in ducts and channels
07.10.Cm Micromechanical devices and systems

Increased frequency shifts in high aspect ratio terahertz split ring resonators

Sher-Yi Chiam, Ranjan Singh, Jianqiang Gu, Jiaguang Han, Weili Zhang, and Andrew A. Bettiol

Appl. Phys. Lett. 94, 064102 (2009); http://dx.doi.org/10.1063/1.3079419 (3 pages) | Cited 25 times

Online Publication Date: 9 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The resonance of split ring resonators (SRRs) is known to shift upon the addition of a dielectric overlayer, a feature useful for practical applications. Here, we demonstrate that the frequency shift is enlarged by increasing the SRR height, thereby potentially enhancing sensitivity and tunability. We fabricated SRRs resonating at terahertz frequencies using a focused proton beam. This resulted in SRRs nearly 10 μm high, with smooth and vertical sidewalls. Terahertz time domain spectroscopy was used for characterization. Upon applying a dielectric overlayer (ϵ = 2.7), a resonance located at 640 GHz shifted by nearly 120 GHz. Simulations also indicate a widening frequency shift as SRR height increases.
Show PACS
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
84.40.-x Radiowave and microwave (including millimeter wave) technology
78.70.Gq Microwave and radio-frequency interactions

Nuclear magnetic resonance implementation of universal quantum gate with constant Hamiltonian evolution

Wenzhang Liu, Jingfu Zhang, Ye Cao, Wen Yi Huo, Liang Hao, Gui Lu Long, and Zhiwei Deng

Appl. Phys. Lett. 94, 064103 (2009); http://dx.doi.org/10.1063/1.3081022 (3 pages) | Cited 4 times

Online Publication Date: 10 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, we report an experimental demonstration of single-step realization of universal quantum gate in a nuclear magnetic resonance quantum information processor. The scheme uses a constant Hamiltonian evolution and is robust against decoherence. Our work focuses on the implementation of the controlled-NOT gate. Several sets of parameters are obtained and they provide flexibility to suppress decoherence for quantum computation.
Show PACS
03.67.Lx Quantum computation architectures and implementations
76.60.-k Nuclear magnetic resonance and relaxation

Terminal velocity and drag reduction measurements on superhydrophobic spheres

G. McHale, N. J. Shirtcliffe, C. R. Evans, and M. I. Newton

Appl. Phys. Lett. 94, 064104 (2009); http://dx.doi.org/10.1063/1.3081420 (3 pages) | Cited 19 times

Online Publication Date: 10 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Super water-repellent surfaces occur naturally on plants and aquatic insects and are created in the laboratory by combining micro- or nanoscale surface topographic features with hydrophobic surface chemistry. When such types of water-repellent surfaces are submerged they can retain a film of air (a plastron). In this work, we report measurements of the terminal velocity of solid acrylic spheres with various surface treatments settling under the action of gravity in water. We observed increases in terminal velocity corresponding to drag reduction of between 5% and 15% for superhydrophobic surfaces that carry plastrons.
Show PACS
47.50.-d Non-Newtonian fluid flows
47.55.D- Drops and bubbles
68.03.Cd Surface tension and related phenomena
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.65.-b Surface treatments

Single crystal growth and formation of defects in deuterium-tritium layers for inertial confinement nuclear fusion

A. A. Chernov, B. J. Kozioziemski, J. A. Koch, L. J. Atherton, M. A. Johnson, A. V. Hamza, S. O. Kucheyev, J. B. Lugten, E. A. Mapoles, J. D. Moody, J. D. Salmonson, and J. D. Sater

Appl. Phys. Lett. 94, 064105 (2009); http://dx.doi.org/10.1063/1.3080655 (3 pages) | Cited 4 times

Online Publication Date: 10 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We identify vapor-etched grain boundary grooves on the solid-vapor interface as the main source of surface roughness in the deuterium-tritium (D–T) fuel layers, which are solidified and then cooled. Current inertial confinement fusion target designs impose stringent limits to the cross-sectional area and total volume of these grooves. Formation of these grain boundaries occurs over time scales of hours as the dislocation network anneals and is inevitable in a plastically deformed material. Therefore, either cooling on a much shorter time scale or a technique that requires no cooling after solidification should be used to minimize the roughness.
Show PACS
81.10.-h Methods of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
61.72.Mm Grain and twin boundaries
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.40.Lm Deformation, plasticity, and creep
52.57.-z Laser inertial confinement

Localized microwave heating in microwells for parallel DNA amplification applications

A. Kempitiya, Diana A. Borca-Tasciuc, Hisham S. Mohamed, and Mona M. Hella

Appl. Phys. Lett. 94, 064106 (2009); http://dx.doi.org/10.1063/1.3078273 (3 pages) | Cited 4 times

Online Publication Date: 10 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This work explores the potential of microwave heating for applications requiring parallel DNA amplification platforms. Device characterization and thermal modeling is performed on 4.1 μl microfluidic chamber fabricated in polycarbonate. Microwave power at 6 GHz is delivered to the chamber via copper transmission line in a microstrip configuration. Microwave power reflection coefficient and temperature measurements are performed to characterize the power coupled to the chamber and rate of change in temperature. Temperatures up to 72 °C are achieved with less than 400 mW power applied at the input of the transmission line. Initial heating and cooling rates measured experimentally are ∼ 7 and ∼ 6 °C/s, respectively. These results suggest that microwave heating is an efficient, rapid heating technique suitable for programmable, parallel DNA amplification platforms to be empolyed in future genetic analysis systems.
Show PACS
87.85.Ox Biomedical instrumentation and transducers, including micro-electro-mechanical systems (MEMS)
47.85.Np Fluidics
87.19.xk Genetic diseases
87.14.gk DNA
87.19.Pp Biothermics and thermal processes in biology
87.85.Va Micromachining

Artificial bacterial flagella: Fabrication and magnetic control

Li Zhang, Jake J. Abbott, Lixin Dong, Bradley E. Kratochvil, Dominik Bell, and Bradley J. Nelson

Appl. Phys. Lett. 94, 064107 (2009); http://dx.doi.org/10.1063/1.3079655 (3 pages) | Cited 82 times

Online Publication Date: 13 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Inspired by the natural design of bacterial flagella, we report artificial bacterial flagella (ABF) that have a comparable shape and size to their organic counterparts and can swim in a controllable fashion using weak applied magnetic fields. The helical swimmer consists of a helical tail resembling the dimensions of a natural flagellum and a thin soft-magnetic “head” on one end. The swimming locomotion of ABF is precisely controlled by three orthogonal electromagnetic coil pairs. Microsphere manipulation is performed, and the thrust force generated by an ABF is analyzed. ABF swimmers represent the first demonstration of microscopic artificial swimmers that use helical propulsion. Self-propelled devices such as these are of interest in fundamental research and for biomedical applications.
Show PACS
07.07.Tw Servo and control equipment; robots
87.85.-d Biomedical engineering
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Laser-generation of ultrasonic X-waves using axicon transducers

K. Passler, R. Nuster, S. Gratt, P. Burgholzer, and G. Paltauf

Appl. Phys. Lett. 94, 064108 (2009); http://dx.doi.org/10.1063/1.3083550 (3 pages) | Cited 3 times

Online Publication Date: 13 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Photoacoustic and classical ultrasound imaging are both based upon ultrasonic waves but use different contrast mechanisms. For the development of a scanning acoustic microscope that uses both contrasts, an axicon transducer generating nondiffracting ultrasound, also called X-waves, by illumination with short laser pulses is investigated. Such a transducer provides simultaneously high depth of field and high lateral resolution. In this work, the spatial and temporal characteristics of the laser-generated X-waves are investigated using experiments and theoretical simulations. The experimental results reveal a characteristic spatial pulse width of 50 μm and a focal depth that complies well with the theoretical predictions.
Show PACS
43.60.Lq Acoustic imaging, displays, pattern recognition, feature extraction
43.58.-e Acoustical measurements and instrumentation
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close