Formation of Supercritical Water under Laser Radiation

Yusupov, V. I.

doi:10.1134/s1990793119070297

Cited by 16 publications

(11 citation statements)

References 97 publications

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“…In this case, the formation of microbubbles and microfoam can occur at a temperature below the boiling point of the liquid due to a sharp decrease in pressure during the passage of a compression wave associated with short-pulse laser heating. It cannot be ruled out that in our case, microbubbles are forming in the polymer matrix by this mechanism [14] during the explosive boiling of formic acid, which is always accompanied by the generation of powerful pressure surges [43].…”

Section: Model Of Laser-induced Formation Of Microstructures In Opbi Filmsmentioning

confidence: 77%

“…Since the volume of this gas, compressed in numerous microcavities, surrounds the polymer material, which is softened due to the increased temperature, the microbubbles will begin to expand sharply (the so-called thermocavitation effect will occur [43]). With this expansion, they will break and grind the polymer material and eventually form one or more expanding macrobubbles.…”

Section: Model Of Laser-induced Formation Of Microstructures In Opbi Filmsmentioning

confidence: 99%

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Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

et al. 2021

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New results are presented for laser formation—in particular, the “drawing” of microstructures in polymer films using continuous-wave (CW) laser radiation λ = 405 nm with an intensity of 0.8–3.7 kW/cm2. The laser drawing was carried out in the polymer system poly-2,2′-p-oxydiphenylene-5,5′-bis-benzimidazole (OPBI), which consists of two phases: a solid polymer matrix with formic acid (HCOOH) dissolved in it. The formation of microstructures, including the stage of foaming, was carried out in three media: air, water and a supercritical carbon dioxide medium containing dissolved molecules of the silver precursor Ag(hfac)COD. The morphological features of foam-like track structures formed in the near-surface layer of the polymer films by laser “drawing” are considered. A model of processes is presented that explains the appearance of periodic structures. The key point of this model is that it considers the participation of the photoinduced mechanism of explosive boiling of formic acid molecules dissolved in the polymer matrix. Using Raman spectroscopy, spectra were obtained and interpreted, which relate to different stages in the formation of microstructures in OPBI films. The effects associated with the peculiarities of luminescent microstructures on the surfaces of glasses in close contact with polymer films during laser “painting” in the air have been studied.

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Section: Model Of Laser-induced Formation Of Microstructures In Opbi Filmsmentioning

confidence: 77%

Section: Model Of Laser-induced Formation Of Microstructures In Opbi Filmsmentioning

confidence: 99%

Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

et al. 2021

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“…If we neglect phase transitions and thermal diffusion due to the short duration of the laser pulse τ , then we can assume that the temperature profile of this thin liquid volume is described by the Gaussian intensity profile in the laser beam. In the axial region of this thin cylindrical volume, in which the water temperature approaches or exceeds the temperature of the spinodal TSp for water, its explosive boiling will occur [28].…”

Section: Resultsmentioning

confidence: 99%

Laser bioprinting without donor plate

Cheptsov¹,

Минаев²,

Zhigarkov³

et al. 2022

Laser Phys. Lett.

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A promising laser bioprinting technology based on the effect of laser-induced direct transfer is rapidly developing and is already actively used in biotechnology and medicine today. Typically, such technologies use donor plates with an absorbent coating, from which gel microdroplets with living cells and microorganisms are transferred to an acceptor substrate under the action of a laser pulse. This article proposes a new bioprinting technology that makes it possible to transfer microdroplet not only without an absorbing coating, but also without the donor plate itself. The essence of this method is that the transfer to the surface of the acceptor is carried out by a series of nanosecond pulse with a wavelength of 3 μm directly from the surface of a liquid with microorganisms. The mechanism of a liquid jet and microdroplets formation upon absorption of a laser pulse in a thin surface liquid layer is discussed in detail. It has been shown that microorganisms transferred using the new bioprinting technology are viable and can be successfully cultivated on a dense nutrient medium.

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“…In cases with an enclosed volume of pore space, the transition to the point of thermal cavitation is observed along with a simultaneous increase in the pressure [26]. When the water reaches the area of the spinodal (T C ≈374 • C), explosive water boiling occurs, and the water in pores transforms into vapor compressed to critical pressure (P C ≈22 MPa) [26,27]. When critical parameters for the tissue are exceeded, such pressure peaks lead to the explosive destruction and formation of shock waves.…”

Section: Optical and Acoustic Testsmentioning

confidence: 99%

Mechanism of Lithotripsy by Superpulse Thulium Fiber Laser and Its Clinical Efficiency

et al. 2020

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Thulium fiber laser with a wavelength of 1.94 µm is widely used in urology for lithotripsy. This paper studies the mechanism of lithotripsy and evaluates its clinical efficiency using the superpulse thulium fiber laser with a wavelength of 1.94 µm and a peak power of 500 W. An experimental setup was developed to study the mechanism of lithotripsy. The superpulse thulium fiber laser (TFL) with a wavelength of 1.94 µm with a peak power of 500 W (FiberLase U2 from “IRE-POLUS” Ltd., Fryazino, Moscow Region, Russia) was used for the lithotripsy of stone phantoms (BegoStone). The processes were recorded with a high-speed camera. The acoustic signals registered during lithotripsy were studied with wideband and needle hydrophones. The main mechanism of lithotripsy performed by using superpulse TFL was thermal cavitation in the water-filled pore space and thermal destruction of the phantom. During the clinical application of the superpulse thulium fiber laser, the high efficiency of laser lithotripsy was established. The performed optical and acoustic studies showed that the mechanism of the destruction of stones was based on the synergic effect of the explosive boiling of water in the pore space of the stone, and its thermal destruction is associated with the heating of the stone to several hundred degrees with laser radiation.

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Formation of Supercritical Water under Laser Radiation

Cited by 16 publications

References 97 publications

Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

Laser-Induced Microstructuring of Polymers in Gaseous, Liquid and Supercritical Media

Laser bioprinting without donor plate

Mechanism of Lithotripsy by Superpulse Thulium Fiber Laser and Its Clinical Efficiency

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