An Analytical Expression Of The Photoacoustic Signal For A Pulsed Laser With A Sinusoidal Radial Profile

The development of photoacoustic systems is important for the real-time detection of cysteine (Cys), a biothiol in biological systems that serves as a significant biomarker for human health. Advanced photoacoustic (PA) signals with colloidal plasmonic Au nanomaterials rely on the efficient conversion of light to energy waves under moderately pulsed laser irradiation. In this study, we synthesized Cys-capped Au nanorods (Au@Cys NRs) and Cys-capped Au nanoparticles (Au@Cys NPs) through a conjugate of three Cys concentrations (10, 100, and 1000 μM). These plasmonic Au nanomaterials can be used as a PA resonance reagent due to their maximum localized surface plasmon resonance (LSPR) absorption bands at 650 nm and 520 nm in Au NRs and Au NPs, respectively. Subsequently, the PA signals were noticeably increased proportionally to the concentrations in the Au@Cys NRs and Au@Cys NPs under 658 nm and 520 nm laser irradiation, respectively, according to our portable photoacoustic system. Furthermore, PA signal amplitudes in Cys detection are boosted by ~233.01% with Au@Cys NRs and ~102.84% with Au@Cys NPs enhancement, compared to free Cys, according to ultrasound transducers at frequencies of 3 MHz.

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Photoacoustic Signal of Nanobubbles Induced in PEGylated Gold-Nanorod Colloid

PISTON: Journal of Technical Engineering ◽

10.32493/pjte.v2i1.3220 ◽

2019 ◽

Vol 2 (1) ◽

Author(s):

Istas Pratomo Manalu

Keyword(s):

Surface Plasmon Resonance ◽

Aspect Ratio ◽

Laser Beam ◽

Ultrasonic Transducer ◽

Pulsed Laser ◽

Photoacoustic Signal ◽

Gold Nanorod ◽

Energy Concentration ◽

Nanosecond Pulsed Laser ◽

Pulsed Laser Beam

We have developed a photoacoustic (PA) measurement system using a broadband ultrasonic transducer to detect the PA signals induced in a gold nanorod (GNRs) colloid irradiated by the nanosecond-pulsed laser beam. This study will investigate the PA signals of PEG-GNRs at longitudinal surface plasmon resonance. Several factors including aspect ratio of GNR, pulse energy, concentration, and wavelength are varied to investigate these effects on the PA signal. We show that at the certain condition the generated PA signal of PEG-GNRs stronger than uncoated GNRs. Moreover, the PA signals of PEGGNRs are more stable than uncoated GNRs in the same condition. Keywords

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The Effects of Laser Energy, Repetition of Pulse Laser, Wavelength, and Temperature on Silver Nano-Particles

Applied Physics Research ◽

10.5539/apr.v10n6p38 ◽

2018 ◽

Vol 10 (6) ◽

pp. 38

Author(s):

F. M. Aldosari ◽

A. M. Azzeer ◽

A. M. Hassib

Keyword(s):

Silver Nanoparticles ◽

Repetition Rate ◽

Laser Energy ◽

Pulsed Laser ◽

Photoacoustic Signal ◽

Laser Wavelength ◽

Nano Particles ◽

Photoacoustic Technique ◽

Input Energy ◽

Effects Of Temperature

To study the effects of temperature, wavelength, laser energy, and repetition of pulsed laser on the silver nanoparticles. The laser induced photoacoustic technique has been used to study photoacoustic properties of silver nanoparticles. The study found a direct correlation between the wavelength and the concentration of the photoacoustic signal. Moreover, an indirect correlation was predicted between the temperature and concentration of the photoacoustic signals. The laser energy was found out to be 355 nm at a constant repetition rate of 2 Hz and the repetition rate of 2 Hz was also selected for the entire measurements. The photoacoustic properties of silver nanoparticles were significantly affected by wavelength, temperature, repetition of pulsed laser, and input energy as predicted by the data collected from the study.

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Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089652 ◽

1991 ◽

Vol 49 ◽

pp. 1068-1069

Author(s):

M. Grant Norton ◽

C. Barry Carter

Keyword(s):

Thin Film ◽

Thin Films ◽

Laser Ablation ◽

Substrate Surface ◽

Pulsed Laser ◽

Pulsed Laser Ablation ◽

Thin Film Deposition ◽

Film Deposition ◽

Laser Ablation Process ◽

Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

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Microanalysis of silicate glass films grown on α-Al2O3 by pulsed-laser deposition

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148022 ◽

1993 ◽

Vol 51 ◽

pp. 438-439

Author(s):

Michael P. Mallamaci ◽

James Bentley ◽

C. Barry Carter

Keyword(s):

Liquid Phase ◽

Single Crystal ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Ceramic Materials ◽

Laser Deposition ◽

Triple Junctions ◽

Ion Milling ◽

Multicomponent Oxides ◽

Glass Films

Glass-oxide interfaces play important roles in developing the properties of liquid-phase sintered ceramics and glass-ceramic materials. Deposition of glasses in thin-film form on oxide substrates is a potential way to determine the properties of such interfaces directly. Pulsed-laser deposition (PLD) has been successful in growing stoichiometric thin films of multicomponent oxides. Since traditional glasses are multicomponent oxides, there is the potential for PLD to provide a unique method for growing amorphous coatings on ceramics with precise control of the glass composition. Deposition of an anorthite-based (CaAl2Si2O8) glass on single-crystal α-Al2O3 was chosen as a model system to explore the feasibility of PLD for growing glass layers, since anorthite-based glass films are commonly found in the grain boundaries and triple junctions of liquid-phase sintered α-Al2O3 ceramics.Single-crystal (0001) α-Al2O3 substrates in pre-thinned form were used for film depositions. Prethinned substrates were prepared by polishing the side intended for deposition, then dimpling and polishing the opposite side, and finally ion-milling to perforation.

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TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151428 ◽

1993 ◽

Vol 51 ◽

pp. 1118-1119

Author(s):

Pamela F. Lloyd ◽

Scott D. Walck

Keyword(s):

Thin Films ◽

Sample Preparation ◽

Room Temperature ◽

High Vacuum ◽

Pulsed Laser ◽

Ultra High Vacuum ◽

Wear Testing ◽

Preparation Technique ◽

Cross Sectional ◽

Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

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On the influence of specimen thickness in TEM images of super-conducting vortices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166087 ◽

1996 ◽

Vol 54 ◽

pp. 724-725

Author(s):

J. Bonevich ◽

D. Capacci ◽

G. Pozzi ◽

K. Harada ◽

H. Kasai ◽

...

Keyword(s):

Flux Line ◽

Analytical Form ◽

Realistic Model ◽

Electron Holography ◽

Specimen Thickness ◽

Flux Tubes ◽

Analytical Expression ◽

Flux Lines ◽

Normal Core ◽

Two Parameters

The successful observation of superconducting flux lines (fluxons) in thin specimens both in conventional and high Tc superconductors by means of Lorentz and electron holography methods has presented several problems concerning the interpretation of the experimental results. The first approach has been to model the fluxon as a bundle of flux tubes perpendicular to the specimen surface (for which the electron optical phase shift has been found in analytical form) with a magnetic flux distribution given by the London model, which corresponds to a flux line having an infinitely small normal core. In addition to being described by an analytical expression, this model has the advantage that a single parameter, the London penetration depth, completely characterizes the superconducting fluxon. The obtained results have shown that the most relevant features of the experimental data are well interpreted by this model. However, Clem has proposed another more realistic model for the fluxon core that removes the unphysical limitation of the infinitely small normal core and has the advantage of being described by an analytical expression depending on two parameters (the coherence length and the London depth).

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Contrast From Point Defects in The Infinitesimal Approximation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001495 ◽

1980 ◽

Vol 38 ◽

pp. 350-351

Author(s):

L. J. Sykes ◽

J. J. Hren

Keyword(s):

Electron Microscope ◽

Point Defects ◽

Broad Class ◽

Stacking Fault ◽

Crystalline Solids ◽

Dislocation Loops ◽

Analytical Expression ◽

Stacking Fault Tetrahedra

In electron microscope studies of crystalline solids there is a broad class of very small objects which are imaged primarily by strain contrast. Typical examples include: dislocation loops, precipitates, stacking fault tetrahedra and voids. Such objects are very difficult to identify and measure because of the sensitivity of their image to a host of variables and a similarity in their images. A number of attempts have been made to publish contrast rules to help the microscopist sort out certain subclasses of such defects. For example, Ashby and Brown (1963) described semi-quantitative rules to understand small precipitates. Eyre et al. (1979) published a catalog of images for BCC dislocation loops. Katerbau (1976) described an analytical expression to help understand contrast from small defects. There are other publications as well.

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