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- 摘要
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[OSA Optical Fiber Communication Conference - San Francisco, California (2014..-..)] Optical Fiber Communication Conference - Biorthogonal Modulation in 8 Dimensions Experimentally Implemented as 2PPM-PS-QPSK
摘要： The influence of ambient air species especially humidity is an ever-present challenge for atmospheric pressure plasma jet applications. Especially, where the plasma-induced effects are extremely sensitive to humidity, such as in the field of plasma medicine, an understanding of the influence of ambient species diffusion on plasma chemistry and on reactive component composition is crucial. In this paper, we investigate the influence of ambient humidity versus feed gas humidity on the production of reactive components by atmospheric pressure plasma jets. By the use of a shielding gas curtain, we control the surrounding atmosphere around the active effluent region of the investigated argon RF-plasma jet the ambient gas. By quantum cascade laser absorption spectroscopy and by Fourier transformed infrared (IR) absorption spectroscopy, the effect of diffusing surrounding molecular species on the chemistry of the long-living reactive oxygen species is investigated. Mechanisms of H2O2 and O3 production are studied. In this paper, we have quantified the influence that ambient species, namely, water molecules, have on the reactive species’ generation in the gas phase. It is shown that the effect of ambient humidity is important for the long-living species production, feed gas humidity, however, has the much stronger effect. Finally, with the focus of applications in plasma medicine, the cell viability of human skin cells (HaCaT keratinocytes) as a function of feed gas and ambient gas humidity is compared.
关键词： Ambient humidity,plasma medicine,feed gas humidity,atmospheric pressure plasma jet,cell viability,plasma chemistry
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE International Conference on Power, Intelligent Computing and Systems (ICPICS) - Shenyang, China (2019.7.12-2019.7.14)] 2019 IEEE International Conference on Power, Intelligent Computing and Systems (ICPICS) - Infrared and Visible Image Fusion Based on CLAHE and Sparse Representation
摘要： The influence of ambient air species especially humidity is an ever-present challenge for atmospheric pressure plasma jet applications. Especially, where the plasma-induced effects are extremely sensitive to humidity, such as in the field of plasma medicine, an understanding of the influence of ambient species diffusion on plasma chemistry and on reactive component composition is crucial. In this paper, we investigate the influence of ambient humidity versus feed gas humidity on the production of reactive components by atmospheric pressure plasma jets. By the use of a shielding gas curtain, we control the surrounding atmosphere around the active effluent region of the investigated argon RF-plasma jet the ambient gas. By quantum cascade laser absorption spectroscopy and by Fourier transformed infrared (IR) absorption spectroscopy, the effect of diffusing surrounding molecular species on the chemistry of the long-living reactive oxygen species is investigated. Mechanisms of H2O2 and O3 production are studied. In this paper, we have quantified the influence that ambient species, namely, water molecules, have on the reactive species’ generation in the gas phase. It is shown that the effect of ambient humidity is important for the long-living species production, feed gas humidity, however, has the much stronger effect. Finally, with the focus of applications in plasma medicine, the cell viability of human skin cells (HaCaT keratinocytes) as a function of feed gas and ambient gas humidity is compared.
关键词： plasma chemistry,atmospheric pressure plasma jet,feed gas humidity,Ambient humidity,plasma medicine,cell viability
更新于2025-09-23 15:19:57
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Expansion dynamics and chemistry evolution in ultrafast laser filament produced plasmas
摘要： Laser ablation in conjunction with optical emission spectroscopy is a potential non-contact, standoff detection method for all elements in the periodic table and certain isotopes such as radionuclides. Currently, significant development efforts are on-going to use ultrafast laser filaments for remote detection of materials. The application of filaments is of particular interest in extending the range of stand-off capability associated with elemental and isotopic detection via laser-induced breakdown spectroscopy. In this study, we characterize the expansion dynamics and chemical evolution of filament-produced uranium (U) plasmas. Laser filaments are generated in the laboratory by loosely focusing 35 femtosecond (fs), 6 milli Joule (mJ) pulses in air. Two-dimensional spectrally-integrated and time-resolved imaging was performed to study hydrodynamics and evolution of U atomic and UO molecular emission in filament-produced U plasmas. Our results highlight that filament ablation of U plasmas gives a cylindrical plasma plume morphology with an appearance of plume splitting into slow and fast moving components at later times of its evolution. Emission from the slow-moving region shows no distinct spectral features (i.e. broadband-like) and is contributed in part by nanoparticles generated during ultrafast laser ablation. Additionally, we find U atoms and U oxide molecules (i.e. UO, UxOy) co-exist in the filament produced plasma, which can be attributed to the generation of low-temperature plasma conditions during filament ablation.
关键词： optical emission spectroscopy,Laser ablation,plasma chemistry,ultrafast laser filaments,uranium plasmas
更新于2025-09-23 15:19:57
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Plasma chemistry produced during laser ablation of graphite in air, argon, helium and nitrogen
摘要： Laser-induced plasma chemistry produced during the ablation of graphite targets at atmospheric pressure in air, argon, helium and nitrogen was studied through time-resolved atomic and molecular emission spectroscopy. The plasma plume and plasma chemistry were generated by focusing a 6-mm diameter, 212 mJ, 1064-nm nanosecond Nd:YAG laser to a spot size of about 1 mm diameter over graphite samples of 99.9% pureness. The atomic emissions C I 247.86 nm, N I 821.50 nm and O I 777.19 nm, and the molecular bands C2 (473.71 nm) and CN (359.04 nm and 388.30 nm) were monitored as a function of time (0.2 to 220 μs). While the C I and C2 emissions followed a near-exponential decay, the CN emission in air and nitrogen showed an emission behavior characterized by two local maxima at 0.2 μs and 20-30 μs after the plasma ignition. The first maximum was explained by the early plasma chemistry produced by the ablated carbon species and the confining background gas, whereas the second maximum was attributed to atomic recombination and shock wave-induced excitation of the plasma plume. Two main effects were observed when the ablation was produced in different background gases. First, the presence of oxygen (≈21%) in air had a negligible effect on atomic lines; however, the CN emission intensity and lifetime were significantly reduced in comparison with an atmosphere of 100% nitrogen. This was attributed to the reduction of nitrogen species as reaction partners during the plasma chemistry in air. Secondly, due to the assumed higher plasma temperature in Ar, this gas favored the emission intensity and lifetime of atomic species but hindered the formation of C2 species. Because the collection optics of the emission spectroscopy system was configured in backscatter mode, which integrates over the entire plasma volume and gate time without spatial resolution, the time-resolved behavior of the plasma emissions were only related to the number density of emitters but not to specific locations in the plasma volume.
关键词： Atomic-molecular emissions,Laser-induced breakdown spectroscopy,Plasma chemistry,Graphite
更新于2025-09-23 15:19:57
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Cold plasma treatment and laser irradiation of <i>Triticum</i> spp. seeds for sterilization and germination
摘要： In this research work, plasma and laser-based treatments have been applied on wheat seeds to improve their growth and development. Plasma treatment modi?ed the surface morphology of seed which enhanced the germination rate and also exhibited great immunity against fungus; only 20% seeds are a?ected by fungus as compared to the untreated sample. In addition, an increase in protein concentration in plasma treated seeds has also been observed. In the laser treatment, laser pulses have been exercised on wheat seeds, while seeds were also exposed in argon plasma generated at di?erent applied voltages and exposure times. This laser treatment lessens germination time, increases water absorption, and abolishes disease development from seed borne fungi that are present on or within seeds. Thus, it is observed that the use of plasma and laser radiation on the seeds made productive e?ects on the growth parameters and may be the alternative source for the presowing seed treatment.
关键词： microbial inactivation,food chemistry,wheat seeds,plasma chemistry,plant biotechnology,cold plasma,germination
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - The Stabilization of the Bolometera??s Heat-Exchange Coefficient with the Environment
摘要： The influence of ambient air species especially humidity is an ever-present challenge for atmospheric pressure plasma jet applications. Especially, where the plasma-induced effects are extremely sensitive to humidity, such as in the field of plasma medicine, an understanding of the influence of ambient species diffusion on plasma chemistry and on reactive component composition is crucial. In this paper, we investigate the influence of ambient humidity versus feed gas humidity on the production of reactive components by atmospheric pressure plasma jets. By the use of a shielding gas curtain, we control the surrounding atmosphere around the active effluent region of the investigated argon RF-plasma jet the ambient gas. By quantum cascade laser absorption spectroscopy and by Fourier transformed infrared (IR) absorption spectroscopy, the effect of diffusing surrounding molecular species on the chemistry of the long-living reactive oxygen species is investigated. Mechanisms of H2O2 and O3 production are studied. In this paper, we have quantified the influence that ambient species, namely, water molecules, have on the reactive species’ generation in the gas phase. It is shown that the effect of ambient humidity is important for the long-living species production, feed gas humidity, however, has the much stronger effect. Finally, with the focus of applications in plasma medicine, the cell viability of human skin cells (HaCaT keratinocytes) as a function of feed gas and ambient gas humidity is compared.
关键词： plasma medicine,cell viability,feed gas humidity,plasma chemistry,Ambient humidity,atmospheric pressure plasma jet
更新于2025-09-19 17:13:59