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In-line whole blood fractionation for Raman analysis of blood plasma
摘要： Blood plasma evaluation has high significance in clinical diagnostics. Current schemes involve the preparation of blood plasma by centrifugation of whole blood followed by electrochemical or spectroscopic analysis. However, centrifugation is often too time-consuming for application in clinical emergency and point-of-care settings. We propose to combine microfluidic, instantaneous plasma fractionation with localized spectroscopic methods for in-line analysis. As an example, we present confocal Raman spectroscopy in fractionated plasma domains at two different Raman excitation wavelengths. Resonance Raman spectroscopy with laser excitation at 408 nm allows the specific detection of free hemoglobin in blood plasma at concentrations above 22 mg dl?1 (level of detection). Consequently, we are able to accurately resolve the range of clinical relevance regarding hemolysis. At near-infrared excitation (785 nm) we furthermore demonstrate the acquisition of characteristic Raman spectra of fractionated blood plasma in the microfluidic setting. These spectra can serve as starting point for a multi-parameter regression analysis to quantify a set of blood plasma parameters from a single Raman spectrum. The combined microfluidics and Raman spectroscopy method is non-destructive and has a whole blood consumption of less than 100 μl per hour. It thus allows for continuous in-line blood plasma monitoring.
关键词： microfluidics,hemoglobin,Raman spectroscopy,blood plasma,clinical diagnostics
更新于2025-09-04 15:30:14
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Simulations of the generation of energetic electrons and the formation of descending artificial plasma layers during HF‐heating at Arecibo
摘要： HF-induced Descending Artificial Plasma Layers (DAPLs) are artificially ionized plasma layers with plasma density in excess of that of the F2-peak. They were discovered during HF heating experiments at HAARP where they descended up to 70 km from the initial O mode wave reflection height. The DAPLs were attributed to the ionization of the neutral gas by high-energy electrons accelerated by the artificial ionospheric turbulence. Recently, DAPL formation was reported during the HF-heating experiment at Arecibo [Bernhardt et al., 2017]. This result was unexpected since Arecibo has the Effective Radiated Power (ERP) 4 – 5 times lower than that at HAARP, and since the experiment at Arecibo also has an unfavorable geometry, where the HF beam is directed vertically while the inclination of the geomagnetic field is 43.5o, allowing the fast electrons to escape the volume where their interaction with the artificial plasma turbulence occurs. However, the presence of photoelectrons due to the UV radiation from the Sun at the low latitude of Arecibo could magnify the flux of hot electrons. A model of artificial plasma layers created by the Arecibo HF facility is presented. It shows that Langmuir turbulence due to the HF heating can accelerate part of the ambient photoelectrons to energies above the ionization threshold of the neutral gas, leading to the formation of DAPLs. The present model results are in quantitative agreement with the experiments of Bernhardt et al. [2017].
关键词： HAARP,HF heating experiments,photoelectrons,HF-induced Descending Artificial Plasma Layers,Arecibo,Langmuir turbulence,DAPLs
更新于2025-09-04 15:30:14
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Fast gas heating of nanosecond pulsed surface dielectric barrier discharge: Spatial distribution and fractional contribution from kinetics
摘要： The effect of heat release in reaction with charged and electronically excited species, or so-called fast gas heating (FGH) in nanosecond surface dielectric barrier discharge (nSDBD) in atmospheric pressure air is studied. 2D numerical simulations based on PASSKEy code (PArallel Streamer Solver with KinEtics code) are conducted. The code is based on the direct coupling of a self-consistent fluid model with detailed kinetics, an efficient photo-ionization model and Euler equations. The choice of local field approximation for nSDBD modeling with simplified kinetics is discussed. The reduced electric field and the electron density are examined at both polarities for the identical high-voltage pulses 24 kV in amplitude on the high voltage electrode and 20 ns FWHM. The distribution of the fast gas heating energy and the resulting gas temperature field are studied and compared with existing references. The input of different reactions to appearing hydrodynamic perturbations is analyzed.
关键词： nanosecond surface dielectric barrier discharge,plasma modeling,fast gas heating,nSDBD
更新于2025-09-04 15:30:14
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Mg induced compositional change in InGaN alloys
摘要： Tunnel junctions are indispensable elements of multi-junction solar cells. The fabrication of InGaN tunnel junctions requires the growth of degenerately doped n- and p-type layers. While highly doped n-type InGaN films have been demonstrated, the growth of degenerately p-doped InGaN films and the fabrication of high indium fraction InGaN tunnel junctions is still to be demonstrated. We present an investigation of the effect of Mg doping on the InGaN crystal properties over a large range of Mg fluxes and InN mole fractions in the range from 30% to 40%, using multiple characterization techniques. InGaN thin films were grown on GaN/sapphire templates and doped with Mg using plasma assisted molecular beam epitaxy (PAMBE). We have found that the Mg concentration in the film increases linearly with the Mg beam equivalent pressure (BEP) at first, followed by a saturation at ~4x1021 cm-3 similar to the Mg doping behavior reported for GaN. The growth rate of the alloy changes by more than 50% with the changes in the surface availability of Mg. These effects can be explained through the saturation of the atomic sites available for incorporation in the case of Mg concentration saturation and by the passivation of the free nitrogen radicals in the case of the growth rate variation. The incorporation of In and Ga depends on the flux ratio (ΦIn + ΦGa) /(ΦMg) at the growth surface and it is shown that the decrease of this ratio below a threshold of ~2000 causes the almost complete loss of In and the formation of a new quaternary wide band gap semiconductor alloy (InGaMg)N.
关键词： In incorporation,(InGaMg)N alloy,Plasma-assisted molecular beam epitaxy,Tunnel junction,Mg-doped P-type InGaN,InGaN
更新于2025-09-04 15:30:14
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Characteristics of Graphene Oxide Films Reduced by Using an Atmospheric Plasma System
摘要： The chemical oxidation method can be used to mass-produce graphene oxides (GOs) from highly oriented pyrolytic graphite. However, numerous oxygen-containing functional groups (hydroxyl, epoxy, carbonyl, etc.) exist in typical GO surfaces, resulting in serious electrical losses. Hence, GO must be processed into reduced graphene oxide (rGO) by the removal of most of the oxygen-containing functional groups. This research concentrates on the reduction efficiency of GO films that are manufactured using atmospheric-pressure and continuous plasma irradiation. Before and after sessions of plasma irradiation with various irradiation times, shelters, and working distances, the surface, physical, and electrical characteristics of homemade GO and rGO films are measured and analyzed. Experimental results showed that the sheet resistance values of rGO films with silicon or quartz shelters were markedly lower than those of GO films because the rGO films were mostly deprived of oxygen-containing functional groups. The lowest sheet resistance value and the largest carbon-to-oxygen ratio of typical rGO films were approximately 90 ?/sq and 1.522, respectively. The intensity of the C–O bond peak in typical rGO films was significantly lower than that in GO films. Moreover, the intensity of the C–C bond peak in typical rGO films was considerably higher than that in GO films.
关键词： sheet resistance,oxygen functional group,GO and rGO films,plasma irradiation,carbon-to-oxygen ratio
更新于2025-09-04 15:30:14
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Surface velocity model of the flow caused by a DBD plasma actuator; DBDプラズマアクチュエータによる流れの表面速度モデル;
摘要： The surface velocity model is proposed for modelling the flow caused by a DBD plasma actuator. While numerical model presented up to now for the DBD plasma actuator, i.e. Suzen’s model, needs to calibrate the five parameters that must be determined by comparison with the experimental results, the surface velocity model presented here requires calibrating three parameters only. The flow by the surface velocity model is compared with the experimental results and that of Suzen’s model. When DBD plasma actuators are activated on the surface of the flat plate or on that of the circular cylinder, the induced flow appears near the electrode. And then the temporal and spatial development of the flow by the surface velocity model is consistent with the results from the experiment and the Suzen’s model. The surface velocity model is very easy to use compared with the Suzen’s model, and it can well simulate the induced flow caused by the plasma actuator.
关键词： Numerical simulation,DBD plasma actuator,Numerical model,Induced flow,Flow control
更新于2025-09-04 15:30:14
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Graphene Synthesis by Plasma-Enhanced CVD Growth with Ethanol
摘要： A modified route to synthesize graphene flakes is proposed using the Chemical Vapor Deposition (CVD) technique, by using copper substrates as supports. The carbon source used was ethanol, the synthesis temperature was 950°C and the pressure was controlled along the whole process. In this CVD synthesis process the incorporation of the carbon source was produced at low pressure and 950°C inducing the appearance of a plasma blue flash inside the quartz tube. Apparently, the presence of this plasma blue flash is required for obtaining graphene flakes. The synthesized graphene was characterized by different techniques, showing the presence of non-oxidized graphene with high purity.
关键词： Chemical Vapor Deposition,Raman Spectroscopy,AFM,Plasma-Enhanced,Graphene Flakes
更新于2025-09-04 15:30:14
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Forward projection matrix derivation through Monte-Carlo ray-tracing of KSTAR infra-red imaging video bolometer (IRVB)
摘要： The infrared imaging video bolometer (IRVB) as a foil bolometry technique can be an alternative solution to the conventional resistive bolometer due to its electro-magnetic immunity and 2D plasma profiles. The plasma profile of the IRVB cannot be directly derived from the foil images due to the difference between the foil pixel number and the plasma pixel number and the line integrated nature of the incident rays on the foil. So, it needs tomography such as the Phillips-Thikhonov algorithm. The projection matrix constructing the foil image from the plasma very directly influences the tomography. So, the projection matrix needs to be constructed precisely. For the technique calculating the precise projection matrix, a forward Monte-Carlo ray-tracing method is proposed here, and this technique can provide the detailed descriptions of the foil image. And it can give enhanced performance in the reconstructions of the plasmas with spatially localized power.
关键词： infrared imaging video bolometer,projection matrix,IRVB,foil bolometry,Monte-Carlo ray-tracing,plasma profile reconstruction
更新于2025-09-04 15:30:14