Picosecond Laser-Induced Hierarchical Periodic Near- and Deep-Subwavelength Ripples on Stainless-Steel Surfaces

Ultrafast laser-induced periodic surface subwavelength ripples, categorized based on the ripple period into near-subwavelength ripples (NSRs) and deep-subwavelength ripples (DSRs), are increasingly found in the variety of materials such as metals, semiconductors and dielectrics. The fabrication of hierarchical periodic NSRs and DSRs on the same laser-irradiated area is still a challenge since the connection between the two remains a puzzle. Here we present an experimental study of linearly polarized picosecond laser-induced hierarchical periodic NSRs and DSRs on stainless-steel surfaces. While experiencing peak power density higher than a threshold value of 91.9 GW/cm2, in the laser-scanned area appear the hierarchical periodic NSRs and DSRs (in particular, the DSRs are vertically located in the valley of parallel NSRs). A large area of the uniformly hierarchical periodic NSRs and DSRs, with the spatial periods 356 ± 17 nm and 58 ± 15 nm, respectively, is fabricated by a set of optimized laser-scanning parameters. A qualitative explanation based on the surface plasmon polariton (SPP) modulated periodic coulomb explosion is proposed for unified interpretation of the formation mechanism of hierarchical periodic NSRs and DSRs, which includes lattice orientation of grains as a factor at low peak power density, so that the initial DSRs formed have a clear conformance with the metallic grains.

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Surface modification of W-Ti coatings induced by TEA CO2 laser beam

Laser and Particle Beams ◽

10.1017/s0263034601192049 ◽

2001 ◽

Vol 19 (2) ◽

pp. 195-199 ◽

Cited By ~ 6

Author(s):

SUZANA PETROVIĆ ◽

B. GAKOVIĆ ◽

M. TRTICA ◽

T. NENADOVIĆ

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Power Density ◽

Peak Power ◽

Laser Action ◽

Laser Pulses ◽

Physicochemical Characteristics ◽

Ti Alloy ◽

Peak Power Density ◽

Aisi 316

In this work, the interaction of a transversely excited atmospheric (TEA) CO2 laser with tungsten–titanium (W-Ti) alloy deposited on austenitic stainless steel is considered. The W-Ti alloy as a refractory material possesses very good physicochemical characteristics such as thermochemical stability and high melting temperature. Studying of interactions of different energetic particles or laser beams with W-Ti coatings has both application and fundamental importance.The morphological features of the W-Ti coating, deposited on austenitic stainless steel AISI 316, induced by a TEA CO2 laser after multipulse cumulative laser action, have been considered. The laser pulses with tail (FWHM = 120 ns, tail = 2 μs) and free-tail pulses (FWHM = 80 ns) have been employed. Laser pulses used in the experiment had equal peak power density I = 120 MWcm−2. For the given peak power density, excessive surface changes on the coating were registered. From direct observation on a microscopic scale (OM, SEM), it can be concluded that W-Ti coatings show different behavior under laser irradiation with various temporal pulse shapes.

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Strong correlation between the peak power density in the time domain and the luminosity of long γ-ray bursts

Chinese Astronomy and Astrophysics ◽

10.1016/j.chinastron.2005.10.002 ◽

2005 ◽

Vol 29 (4) ◽

pp. 361-369 ◽

Cited By ~ 1

Author(s):

Zhao-yu Yang ◽

Li-ming Song ◽

Rong-feng Shen ◽

Zhuo Li ◽

Yu-sheng Lu

Keyword(s):

Power Density ◽

Time Domain ◽

Strong Correlation ◽

Peak Power ◽

Peak Power Density ◽

Γ Ray ◽

The Time Domain

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Investigation of Transport Phenomena in Micro Flow Channels for Miniature Fuel Cells

1st International Fuel Cell Science, Engineering and Technology Conference ◽

10.1115/fuelcell2003-1711 ◽

2003 ◽

Cited By ~ 8

Author(s):

S. W. Cha ◽

S. J. Lee ◽

Y. I. Park ◽

F. B. Prinz

Keyword(s):

Fuel Cell ◽

Power Density ◽

Peak Power ◽

Gas Flow ◽

Transport Phenomena ◽

Cell Performance ◽

Peak Power Density ◽

Micro Channels ◽

Model Predictions ◽

The Impact

This paper presents a study on the transport phenomena related to gas flow through fuel cell micro-channels, specifically the impact of dimensional scale on the order of 100 microns and below. Especially critical is the ability to experimentally verify model predictions, and this is made efficiently possible by the use of structural photopolymer (SU-8) to directly fabricate functional fuel cell micro-channels. The design and analysis components of this investigation apply 3-D multi-physics modeling to predict cell performance under micro-channel conditions. Interestingly, the model predicts that very small channels (specifically 100 microns and below) result in a significantly higher peak power density than larger counterparts. SU-8 micro-channels with different feature sizes have been integrated into fuel cell prototypes and tested for comparison against model predictions. The results not only demonstrate that the SU-8 channels with metal current collector show quite appreciable performance, but also provide experimental verification of the merits of channel miniaturization. As predicted, the performance in terms of peak power density increases as the feature size of the channel decreases, even though the pressure drop is higher in the more narrow channels. So it has been observed both theoretically and experimentally that cell performance shows an improving trend with micro-channels, and design optimization for miniature fuel cell provides a powerful method for increasing power density.

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The Influence of Mediator Concentration on the Performance of Microbial Fuel Cell

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.512-515.1520 ◽

2012 ◽

Vol 512-515 ◽

pp. 1520-1524 ◽

Cited By ~ 1

Author(s):

Yu Zhao ◽

Xiao Bin Wang ◽

Peng Li ◽

Yan Ping Sun

Keyword(s):

Methylene Blue ◽

Fuel Cell ◽

Microbial Fuel Cell ◽

Power Density ◽

Peak Power ◽

Electrochemical Impedance ◽

Peak Power Output ◽

Anode Potential ◽

High Concentration ◽

Peak Power Density

Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), power density and anode potential are used to characterize the mediator microbial fuel cell at different methylene blue (MB) concentrations. At lower MB concentration between 9.98×10-3 mmol/L and 1.66×10-1 mmol/L, the increased power density is enabled by using high mediator concentrations. Higher peak power density of 159.6 mw/m2 is observed compared with the peak power density of 36.0 mw/m2. But MB at too high concentration is disadvantageous to the perform of MFC. At the MB concentration of 2.50×10-1 mmol/L, the peak power output is just 128.4 mw/m2, which is lower than 159.6 mw/m2 at MB concentration of 1.66×10-1 mmol/L.

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Carbon Nanotube Free-Standing Membrane of Pt/SWNTs as Catalyst Layer in Hydrogen Fuel Cells

Australian Journal of Chemistry ◽

10.1071/ch06411 ◽

2007 ◽

Vol 60 (7) ◽

pp. 528 ◽

Cited By ~ 10

Author(s):

Jason M. Tang ◽

Kurt Jensen ◽

Wenzhen Li ◽

Mahesh Waje ◽

Paul Larsen ◽

...

Keyword(s):

Carbon Nanotube ◽

Fuel Cell ◽

Power Density ◽

Peak Power ◽

Proton Exchange Membrane ◽

Catalyst Layer ◽

Proton Exchange ◽

Free Standing ◽

Peak Power Density ◽

Exchange Membrane

A simple and promising fuel-cell architecture is demonstrated using a carbon nanotube free-standing membrane (CNTFSM) made from Pt supported on purified single-walled carbon nanotubes (Pt/SWNT), which act as the catalyst layer in a hydrogen proton exchange membrane fuel cell without the need for Nafion in the catalyst layer. The CNTFSM made from Pt/SWNT at a loading of 0.082 mg Pt cm–2 exhibits higher performance with a peak power density of 0.675 W cm–2 in comparison with a commercially available E-TEK electrocatalyst made of Pt supported on XC-72 carbon black, which had a peak power density of 0.395 W cm–2 at a loading of 0.084 mg Pt cm–2 also without Nafion in the catalyst layer.

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The fast optimal voltage partitioning algorithm for peak power density minimization

2010 IEEE/ACM International Conference on Computer-Aided Design (ICCAD) ◽

10.1109/iccad.2010.5654144 ◽

2010 ◽

Cited By ~ 1

Author(s):

Jia Wang ◽

Shiyan Hu

Keyword(s):

Power Density ◽

Peak Power ◽

Peak Power Density ◽

Partitioning Algorithm

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Application of platinum-cobalt-boron as the anode material for sodium borohydride-hydrogen peroxide fuel cells

Chemija ◽

10.6001/chemija.v29i4.3838 ◽

2018 ◽

Vol 29 (4) ◽

Cited By ~ 1

Author(s):

Aldona Balčiūnaitė ◽

Zita Sukackienė ◽

Loreta Tamašauskaitė-Tamašiūnaitė ◽

Rimantas Vaitkus ◽

Eugenijus Norkus

Keyword(s):

Hydrogen Peroxide ◽

Fuel Cells ◽

Fuel Cell ◽

Power Density ◽

Anode Materials ◽

Peak Power ◽

Anode Catalysts ◽

Fuel Cell Performance ◽

Peak Power Density ◽

Density Values

The electroless deposition and galvanic displacement methods were used for the fabrication of cobalt–boron (CoB) catalysts modified with small amounts of platinum crystallites in the range of 9.8 to 14.4 μgPt cm–2. The prepared catalysts were studied as the anode materials for direct borohydride–hydrogen peroxide (NaBH4/H2O2) fuel cells at temperatures of 25–55°C. Polarization curves have been recorded with the aim to evaluate the fuel cell performance using the prepared CoB and that modified with Pt crystallites as the anode catalysts. For all catalysts (pure CoB and PtCoB) investigated, the peak power density values increase consecutively with the increment in temperature from 25°C up to 55°C. The values from 86–146 mV cm–2 and 146–234 mV cm–2 were determined for pure CoB and PtCoB catalysts, respectively. The highest specific peak power density of 21.5 kWgPt–1 was achieved at 55°C temperature when the PtCoB catalyst with the Pt loading of 9.8 μgPtcm–2 was employed as the anode catalyst in the NaBH4/H2O2 single fuel cell.

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Human auditory system response to modulated electromagnetic energy

Journal of Applied Physiology ◽

10.1152/jappl.1962.17.4.689 ◽

1962 ◽

Vol 17 (4) ◽

pp. 689-692 ◽

Cited By ~ 92

Author(s):

Allan H. Frey

Keyword(s):

Power Density ◽

Peak Power ◽

Acoustic Noise ◽

Average Power ◽

Critical Factor ◽

Electromagnetic Energy ◽

Acoustic Energy ◽

System Response ◽

Peak Power Density ◽

Energy Sensor

The intent of this paper is to bring a new phenomenon to the attention of physiologists. Using extremely low average power densities of electromagnetic energy, the perception of sounds was induced in normal and deaf humans. The effect was induced several hundred feet from the antenna the instant the transmitter was turned on, and is a function of carrier frequency and modulation. Attempts were made to match the sounds induced by electromagnetic energy and acoustic energy. The closest match occurred when the acoustic amplifier was driven by the rf transmitter's modulator. Peak power density is a critical factor and, with acoustic noise of approximately 80 db, a peak power density of approximately 275 mw/ cm2 is needed to induce the perception at carrier frequencies of 425 mc and 1,310 mc. The average power density can be at least as low as 400 μw/cm2. The evidence for the various possible sites of the electromagnetic energy sensor are discussed and locations peripheral to the cochlea are ruled out.

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