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Modular Ceramic-Polymeric Device for Analysis of Selected Elements in Liquid Using Microplasma
摘要： Miniaturization of devices for analysis of chemical composition is being still developed. In this article we present a portable device with a microplasma excitation source. The microdischarge is ignited inside a ceramic structure between a solid anode and a liquid cathode. As a result of cathode sputtering of the solution, it is possible to determine its chemical specimens by analysis of emission spectra of the microdischarge. We fabricated cathodes with a microfluidic compartment and two types of anodes. Devices were tested experimentally. Spectroscopic properties of the microdischarge and its analytical performance depended on the used ceramic structure, the surface area of the cathode aperture and the flow rate of the solution.
关键词： optical emission spectroscopy,microplasma,LTCC
更新于2025-09-23 15:23:52
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Spectroscopic diagnostics of continuous and transient microplasma formed in a millimeter wave photonic crystal
摘要： We present spectroscopic measurements of a microplasma formed within a photonic crystal (PhC) at argon gas pressures up to 750 Torr. Continuous and pulsed millimeter waves (MMW) generate plasma at a vacancy defect within the crystal. Rotational gas temperatures of 300-1050 K and electron densities of 0.5-2×1020 m-3 are obtained from the CH rotational emission spectrum and from Stark broadening of the ???? atomic transition. Electron density is found to be weakly dependent on MMW power because the plasma expands within the defect volume at higher power. Pulsed MMWs slightly increase the peak electron density compared to continuous waves with the same peak power. With MMW pulses, a rapid decrease of wave transmission through the PhC is observed at the beginning of plasma formation. During plasma ignition two distinct plasmas are formed, one on the conducting wall of the PhC near the optical access port and a second within the center of the PhC defect. With longer periods between pulses, the weak wall plasma is observed to form before the principal plasma in the defect, which aids in initiating the main plasma.
关键词： photonic crystal,millimeter waves,electron density,spectroscopic diagnostics,microplasma,gas temperature
更新于2025-09-23 15:19:57
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Features of fused silica ablation by laser induced carbon microplasma
摘要： The features of surface structuring on the transparent material by laser-induced microplasma were studied and the intensity of its microplasma was measured. The formation of micro-relief by a series of nanosecond pulsed laser induced carbon microplasma in confinement mode on the surface of fused silica were investigated and the measured intensity was compared with the features of micro-relief. The dependence of depth of formed relief and track on the laser regime was determined. It is shown that the mechanism of microstructure formation is dependent on multifactor and associated with the ablation on the surface of fused silica by the microplasma, which exists quite long time after the pulses.
关键词： Ablation,Surface structuring,Laser-induced microplasma,Nanosecond pulses,Fiber laser,Fused silica
更新于2025-09-23 15:19:57
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Simple Universal Strategy for Quantification of Carboxyl Groups on Carbon Nanomaterials: Carbon Dioxide Vapor Generation Coupled to Microplasma for Optical Emission Spectrometric Detection
摘要： The physicochemical properties and applications of carbon nanomaterials are remarkably dependent on the amount of carboxyl group on their surfaces. Unfortunately, it is challenging to determine the carboxyl group on carbon nanomaterials at an ultralow density not only due to the low sensitivities of conventional techniques, but also because there are no matrix-matched certi?ed reference materials available. In this work, a novel strategy comprising coupling carbon dioxide vapor generation to a microplasma optical emission spectrometer was developed for the sensitive and accurate quanti?cation of surface carboxyl groups on carbon nanomaterials. The carboxyl group on multiwall carbon nanotubes (MWCNTs), graphene (G), or its oxide (GO) was converted to carboxylic acid using concentrated hydrochloric acid prior to quanti?cation. The generated carboxylic acid was puri?ed and then reacted with sodium bicarbonate to generate CO2, which was swept into a miniaturized point discharge optical emission spectrometer (μPD-OES) for the detection of carbon atomic emission lines. Potassium hydrogen phthalate (KHP) served as a calibration standard for quanti?cation of the carboxyl group on G/GO/MWCNTs, thus, overcoming the lack of CRMs. Owing to the high sensitivity of μPD-OES for the detection of CO2, a limit of detection of 0.1 μmol g?1 (1 nmol) was obtained for the carboxyl group based on a sample mass of 10 mg G/GO/MWCNTs, superior to that obtained using conventional methods. Moreover, the proposed method not only retains several unique advantages of good accuracy and elimination of the use of complicated, expensive, and high power-consumption instruments, but was also applicable to the quanti?cation of the carboxyl group on other nanomaterials such as carboxylated magnetic microspheres.
关键词： carbon dioxide vapor generation,microplasma optical emission spectrometer,carbon nanomaterials,quantification,carboxyl groups
更新于2025-09-23 15:19:57
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Microstructured SiOx thin films deposited from hexamethyldisilazane and hexamethyldisiloxane using atmospheric pressure thermal microplasma jet
摘要： Microstructured silicon oxide (SiOx) thin films were deposited on glass and metal substrates from 1,1,1,3,3,3-hexamethyldisilazane (HMDSN) and hexamethyldisiloxane (HMDSO) by using atmospheric-pressure thermal microplasma jet. Two kinds of string-like products, randomly bent string-like products and linear string-like products, were deposited and they formed microstructured films. The bent string-like products formed labyrinth-like structures and the linear string-like products lay in parallel to form a large aligned structure. The width of both the bent and linear string-like products was from 1 to 3 μm, regardless of the kind of the precursor but depending on the plasma irradiation conditions. The influence of various surface microstructure of substrates on the formation of the SiOx microstructure was investigated to make clear the mechanism for the formation of the microstructures.
关键词： Atmospheric pressure microplasma,Thin film,Microstructure,Silicon oxide
更新于2025-09-10 09:29:36
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Plasma spatial distribution manipulation and electrical property enhancement through plasma coupling effect
摘要： Plasma pattern transition in a symmetric hybrid structure cavity device at micrometer scale is researched through microplasma interaction in intervening microchannel between adjacent cavities while manipulating electric field strength. Plasma distribution reconfiguration in central (objective) cavity is observed when sidearm (donor) cavities are ignited. As long as coupling effect occurred by modulating the electric field strength in the sidearm cavities, stable plasma pattern transition in objective cavity is obtained, exhibiting plasma pattern split from one circular spot (initial pattern) to two small circular spots (transited pattern), along with plasma peak emission intensity displacement over 100 μm to its equilibrium position. The shape of transited plasma patterns are depending on the coupling effect from sidearm cavities. The two circular spots unsymmetrically distributed if either donor cavity is ignited, and the ratio of average emission intensity between the two plasma spots is over 30%, however, which is less than 4% if coupling symmetrically occurred. The electrical and optical properties of central microplasma are also modulated, that the breakthrough voltage is decreased by 22% and emission intensity is improved by ～30%, by means of plasma coupling. The microplasma pattern formation at micrometre scale and manipulation of the electrical properties in microscale cavity implies significant value in the application of plasma transistor and signal processing.
关键词： microscale cavity,plasma pattern transition,plasma coupling effect,electric field strength,microplasma interaction
更新于2025-09-10 09:29:36