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CW lasera??initiated formation of nanoa??Si crystals in glassa??metal nanostructures
摘要： Local and controllable growth of nanocrystalline silicon (nano-Si) in a commercial borosilicate glass is demonstrated. The nano-Si was formed in the subsurface region of the glass via aluminothermic reaction in the course of the irradiation of a 2D array of aluminum nanodisks fabricated on the glass surface with CW low-power 633 and 532 nm lasers. The thermoplasmonic nature of the nanodisks heating is demonstrated: at low incident intensity, the phenomenon takes place only if the plasmon resonance of the array and the laser wavelength are close enough. However, when the laser beam intensity at the sample surface exceeds 8 MW/cm2 mutual position of the plasmon resonance and the laser wavelength weakly influences the phenomenon. The nano-Si formation is studied with Raman scattering technique, and the average size of the silicon nanocrystals is evaluated.
关键词： nanocrystalline silicon,thermoplasmonic heating,aluminothermic reaction,laser irradiation,Raman scattering
更新于2025-09-19 17:13:59
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Linear and nonlinear optical properties change in Ag/GeS heterostructure thin films by thermal annealing and laser irradiation
摘要： The photo and thermal annealing induced linear and nonlinear optical properties, structural properties and surface morphology of thermally evaporated Ag/GeS bilayer thin films are reported in the present study. The related changes due to Ag diffusion into GeS layer by annealing at 200 °C and 532 nm laser irradiation have been probed. The X-ray diffraction revealed no structural change whereas the surface structure was viewed by field emission scanning electron microscopy. The optical data recorded by UV–visible spectrophotometer in the range of 500–1200 nm shows the decrease in refractive index (n) and extinction coefficient (k). The Ag diffusion into GeS layer increased the optical band gap due to the decrease of width of the localised states. The single oscillator Wemple–Di Domenico model was used to study the dispersion relation. The third order nonlinear susceptibility (χ(3)) and nonlinear refractive index (n2) were calculated by using suitable semi-empirical relation. The change in density of defects and localised states explained the observed linear and nonlinear changes with annealing and laser irradiation. The homopolar bond to heteropolar bond transformation is noticed from X-ray photoelectron spectroscopy. The observed optical changes can be used in various optical applications.
关键词： Annealing,Laser irradiation,Optical properties,Refractive index,Thin films,Nonlinear properties
更新于2025-09-19 17:13:59
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Modulation of Plasticity of All-metal Oxide Synaptic Transistor via Laser Irradiation
摘要： Artificial intelligence device mimicking human brains is the foundation for building future artificially neural networks. A key step to mimic biological neural systems is the modulation of synaptic weight, which is mainly achieved by various engineering approaches with materials design or modification of device structure. Here, we realized the modulation of synaptic weight of Ta2O5/ITO based all-metal oxide synaptic transistor via laser irradiation. Prior to the deposition of active layer and electrodes, fs-laser was induced to irradiate on the surface of insulator layer. The typical synaptic characteristics such as excitatory post synaptic current (EPSC), paired pulse facilitation (PPF) and long term potentiation (LTP) were successfully simulated under different laser intensities and scanning rates. Particularly, we demonstrated for the first time that laser irradiation could control the amount of oxygen vacancies in the Ta2O5 thin film, leading to the precise modulation of synaptic weight. Our research provides an instantaneous(<1s), convenient and low-temperature approach to improve synaptic behaviors, which would be promising for neuromorphic computing hardware design.
关键词： synaptic transistor,laser irradiation,oxygen vacancy,Ta2O5
更新于2025-09-19 17:13:59
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The time fractional approach for the modeling of thermal therapies: Temperature analysis in laser irradiation
摘要： In this study we assessed the use of the fractional derivative formulation of the heat transmission equation (FDHTE) as an alternative to the classical or parabolic heat transfer equation (PHTE) in the mathematical modeling of some thermal therapy processes. We obtained the FDHTE analytical solutions in two cases: a general case of heat transfer in a finite bar with different and constant temperature in its extremes (without heat source), and the heating by a laser source of a semi-infinite medium which includes a heat source and it was considered in thermal therapies to destroy or alter biological tissue. Both solutions were obtained analytically and compared with the PHTE results. We also compared the FDHTE solution with the results of the hyperbolic heat transfer equation (HHTE), which is another alternative to the PHTE, but is only used for problems in which intense heat is applied to materials for very short times. The results show that the FDHTE can be used as an alternative to the PHTE in thermal therapy processes in which the PHTE theoretical models underestimate or overestimate the temperatures achieved in tissue. Unlike the HHTE, the FDHTE is not restricted to special problems only. We have thus laid the groundwork for the analytical resolution of the problems considered by the FDHTE.
关键词： Time fractional equation,Fractional derivative equation,Thermal therapies,Heat equation,Laser irradiation
更新于2025-09-19 17:13:59
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The Protozoan, <i>Paramecium primaurelia</i> , as a Non-sentient Model to Test Laser Light Irradiation: The Effects of an 808nm Infrared Laser Diode on Cellular Respiration
摘要： Photobiomodulation (PBM) has been used in clinical practice for more than 40 years. Unfortunately, conflicting literature has led to the labelling of PBM as a complementary or alternative medicine approach. However, past and ongoing clinical and research studies by reputable investigators have re-established the merits of PBM as a genuine medical therapy, and the technique has, in the last decade, seen an exponential increase in the numbers of clinical instruments available, and their applications. This resurgence has led to a clear need for appropriate experimental models to test the burgeoning laser technology being developed for medical applications. In this context, an ethical model that employs the protozoan, Paramecium primaurelia, is proposed. We studied the possibility of using the measure of oxygen consumption to test PBM by irradiation with an infrared or near-infrared laser. The results show that an 808nm infrared laser diode (1W; 64J/cm2) affects cellular respiration in P. primaurelia, inducing, in the irradiated cells, a significantly (p < 0.05) increased oxygen consumption of about 40%. Our findings indicate that Paramecium can be an excellent tool in biological assays involving infrared and near-infrared PBM, as it combines the advantages of in vivo results with the practicality of in vitro testing. This test represents a fast, inexpensive and straightforward assay, which offers an alternative to both traditional in vivo testing and more-expensive mammalian cellular cultures.
关键词： laser irradiation,mitochondria,low level laser therapy,high level laser therapy,photobiostimulation,laser phototherapy
更新于2025-09-16 10:30:52
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Thermodynamics of Natural Pigment-Doped Ethanol under Monochromatic Laser Irradiation
摘要： A laser beam heats a mixture of ethanol and anthocyanins producing the effect of a reciprocating machine. This behaviour is analyzed in terms of the stable, metastable and unstable states of Landau and Lifschitz. Trying first with the van der Waals equation of state, with negative results because the system state is normally far from the critical state, a modified version, with van der Waals coefficients depending linearly on the temperature is proposed, based in the thermodynamic properties of ethanol at room and critical temperatures. The resulting theory allows us to understand the discontinuous results concerning the absorption of the laser beam in terms of a thermodynamic cycle and its frequency dependence on the laser light focus position. Slight changes in the experimental setup may enable the measurement of thermodynamic properties in metastable states.
关键词： Ethanol,van der Waals Equation,Laser Irradiation,Thermodynamics,Natural Pigments
更新于2025-09-16 10:30:52
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Damage Evaluation of TBC by Rapid Thermal Cycling Test Utilizing a Laser Irradiation
摘要： Thermal barrier coating (TBC) is deposited onto the gas turbine blade surface in order to protect the substrate from high-temperature combustion gas. Cracks and delamination of the ceramic coating which come from high heat flux loading are serious problem in TBC. In this study, the rapid thermal cycling device utilizing laser irradiation was developed. It was then investigated how the damage progresses in the ceramic coating exposed to cyclic rapid thermal loading. As a result, a sintering layer was formed in the surface of the ceramic coating, although such phenomenon was not recognized in TBC sample tested by the conventional thermal cycling test using an electric furnace. It was also revealed from the cross-sectional observation that the vertical crack was initiated at the surface of TBC and propagated into sintering layer. Finally, mechanical factors of those damages from finite element analysis using the TBC model including sintering progress was discussed.
关键词： Thermal Barrier Coatings,Gas Turbine,Finite Element Analysis,Laser irradiation
更新于2025-09-16 10:30:52
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Coupled Thermal-Mechanical Analysis of CO<sub>2</sub> Laser Irradiation on Fused Silica
摘要： To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO2 laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO2 laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.
关键词： fused silica,laser irradiation,ductile grinding,viscoelastic,residual stress
更新于2025-09-16 10:30:52
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External Laser Irradiation; レーザー外照射;
摘要： Sclerotherapy is an effective treatment for web-type and reticular-type. However, it is ineffective in some cases of small spider veins. We discuss the clinical outcomes of external laser irradiation for web-type and reticular-type, as well as the techniques, history, and principles of external laser irradiation. The study included 68 patients (109 legs) with a mean age of 47.9±10.6 years. A total of 67 patients (108 legs) were women and only 1 patient (1 leg) was a man, and 22.3% of all patients were foreigners. In other words, relatively young women and foreigners wished to undergo the procedure. Anesthesia was performed by a topical application of lidocaine tape (18 mg Penles Tape). There were no severe complications such as skin necrosis or pigmentation. A relatively large proportion of patients (n=21, 31.3%) also underwent sclerotherapy. Our findings suggest that sclerotherapy and external laser irradiation should be selected appropriately based on the type and range of veins affected.
关键词： reticular-type,sclerotherapy,web-type,external laser irradiation
更新于2025-09-16 10:30:52
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Effect of diode laser on physical properties of CdS thin films
摘要： In this study, Cadmium Sulphide (CdS) thin films are deposited on glass substrates by means of Spray Pyrolysis method to examine the influence of electromagnetic and optical features of these films by diode laser. Accordingly, samples are feasibly irradiated by laser pointer with a power of 500 mw and a wavelength of 532 nm at distance of 10 cm from the source during dissimilar exposure times of 10,20,30,40,50,60,70 and 80 minutes. The absorbance spectrums have been measured by UV-visible spectrophotometer under range of 190-1100 nm .Optical parameters such as transmission , reflection ,absorption coefficient (α), extinction coefficient (K), optical band gap (Eg), refractive index (n), and complex dielectric constants were evaluated from absorbance spectra. The results shows that the laser pointer irradiation cause decreased in transmittance (T), reflectance (R), absorption coefficient α, the extinction coefficient (K), refractive index (n) and the real and imaginary parts of dielectric constant and decrease in the value of the energy gap (Eg). In study of FTIR-spectrum of CdS films in different ratio of irradiation times, there was no change in the peak positions just bigger or smaller with increase in times of irradiation.
关键词： Cadmium Sulfide (CdS),Laser Irradiation,Electromagnetic and Optical Properties,Spray Pyrolysis,Thin Film
更新于2025-09-16 10:30:52