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On the possibility of the electron-beam welding of quartz glasses by a forevacuum plasma electron source
摘要： The article demonstrates a principle possibility of the electron-beam welding of high-temperature quartz glasses by a plasma electron source operating in the forevacuum range of pressure of 10-50 Pa. We studied the dependence of the composition of the gas atmosphere in the vacuum chamber on the heating temperature of the weld seam. It is shown that the optimal temperature of the weld seam for melting and minimum mass entrainment from the molten pool is 1300 to 1400 0C. We determined the welding regime for cylindrical tubes and rods that provides high seam strength, reaching 90-95% of the original strength of quartz glass.
关键词： forevacuum range of pressure,electron-beam welding,plasma electron source,quartz glass
更新于2025-09-10 09:29:36
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Enhanced photocatalytic activity and photocurrent properties of plasma-synthesized indium-doped zinc oxide nanopowder
摘要： Zinc oxide and indium-doped zinc oxide (IZO) nanopowders (wurtzite crystal phase) were synthesized by plasma-assisted chemical vapor synthesis route. In this method, the injected precursors were vaporized in the plasma flame, followed by vapor-phase reaction and subsequent quenching of the vaporized materials, resulting in the formation of nanoparticles. The amount of indium nitrate was varied to obtain 4 at. % and 8 at. % indium incorporated in zinc oxide, designated as ‘IZO1’ and ‘IZO2’, respectively. UV–visible absorbance spectra of the product showed a redshift in the spectra with increasing doping amount of indium. Photocatalytic properties of ZnO and IZO nanoparticles were evaluated using the degradation of methylene blue (MB) under ultraviolet irradiation, and the kinetic analyses indicated that the photodegradation followed pseudo-first order kinetics. In addition, IZO1 nanoparticles exhibited superior photocatalytic activity to ZnO and IZO2 nanoparticles, and the enhancement was attributed to the low recombination rate of photogenerated charge carriers. The major role of defect concentrations (oxygen vacancies) toward MB degradation was also analyzed by Raman and XPS spectra. The effect of scavengers in the photodegradation process indicated that h+ and O2? were the main oxidant species involved in the degradation process. A mechanism of photodegradation process in IZO was proposed based on Mulliken electronegativity approach. Enhanced photocurrent density was obtained in IZO1, and the electrochemical impedance spectroscopy (EIS) results also pointed to an enhanced separation efficiency of electrons and holes at a lower indium doping amount as in IZO1.
关键词： ZnO,Plasma synthesis,IZO,Photocatalysis,Photocurrent,Indium-doped zinc oxide
更新于2025-09-10 09:29:36
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Reconstruction and analysis of exploding wire particle trajectories via automatic calibration of stereo images
摘要： Quantitative understanding of the physics of dust or granular matter transport significantly impacts several aspects of burning plasma science and technology. This work takes machine vision techniques popular in robotics and self-driving cars and applies them to identification and analysis of microparticles generated from exploding wires. Using only the image frames and knowledge of the intrinsic properties of the cameras, a Python code was written to identify the particles, automatically calibrate the relative image positions, and extract trajectory data. After identifying approximately 50 particles based on the timing of secondary particle explosions, the eight point and random sample consensus algorithms were used to determine the geometric correlation between the cameras. Over 100 particle matches were found between the two camera views. These correlated trajectories were used in subsequent 3D track reconstruction and analysis of the physics behind the particle motion. The 3D reconstruction resulted in accurate positioning of the particles with respect to the experimental setup. The particle motion was consistent with the effects of a 1 g gravitational field modified by drag forces. The methods and analyses presented here can be used in many facets of high temperature plasma diagnostics.
关键词： stereo images,automatic calibration,plasma diagnostics,particle trajectories,3D reconstruction,exploding wire
更新于2025-09-10 09:29:36
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Comparison of mechanisms of the plasma generation by nanosecond discharge at extremely high overvoltage
摘要： Two mechanisms of the nanosecond timescale discharge initiation in nitrogen at extremely high overvoltage are compared using a one-dimensional Particle-in-Cell Monte Carlo collisions model. In the first mechanism, the discharge is ignited by the electrons seeded initially in the vicinity of the cathode, while in the second mechanism, the discharge is initiated by the electron field emission from the cathode. It was shown that both approaches predict discharge evolution governed by the runaway electrons generating in the cathode-anode gap. The latter promotes the propagation of the fast ionization wave from the cathode to the anode. However, there are some distinctive features which are explained by different numbers of runaway electrons presented in the cathode-anode gap. In the case, when the field emission is considered, one obtains the virtual cathode formation, the generation of electrons with the anomalous energy, and the fast ionization wave velocity comparable to the speed of light.
关键词： nanosecond discharge,runaway electrons,fast ionization wave,plasma generation,field emission
更新于2025-09-10 09:29:36
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Raman Scattering by Plasma Oscillations in Quantum Rings
摘要： Resonant Raman scattering in quantum rings with a sufficiently large number of conduction electrons has been studied. The cross section for Raman scattering accompanied by the excitation of a one-dimensional plasmon in a ring has been determined in the self-consistent field approximation.
关键词： self-consistent field approximation,Raman scattering,quantum rings,plasma oscillations
更新于2025-09-10 09:29:36
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Large Area Three-Dimensional Photonic Crystal Membranes: Single-Run Fabrication and Applications with Embedded Planar Defects
摘要： Three-dimensional photonic crystals (3D PhCs) enable light manipulations in all three spatial dimensions, however, real world applications are still faced with challenges in fabrication. Here, a facile fabrication strategy for 3D silicon PhCs with a simple cubic (SC) lattice structure is presented, which exhibits a complete photonic bandgap at near-infrared wavelengths of around 1100 nm. The fabrication process is composed of standard deep ultra-violet stepper lithography, followed by a single-run modified plasma etch process. By applying a direct dry etch release step at the end of the 3D structural etch process, the fabricated 3D PhCs can be released and transferred in the form of a membrane onto other substrates such as glass, polymers, or even substrates with engineered surface. The thickness of the demonstrated membranes is around 2 μm and the size can be up to a few millimeters. A high reflectivity is observed at the stop band frequency, and a planar defect is introduced during the etching process resulting in an optical resonance mode with a small linewidth of around 30 nm. The structure constitutes an optical bandpass filter and can be used as a sensor for organic solvents.
关键词： silicon,3D photonic crystals,planar cavities,plasma etching,DREM process
更新于2025-09-10 09:29:36
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P-6.1: Asymmetric Effects of Gate-Bias Stress Voltage on the Stability under Positive and Negative Gate-Bias Stress of a-IGZO TFTs
摘要： The asymmetric effects of gate-bias stress voltage on the stability under positive gate-bias stress (PBS) and negative gate-bias stress (NBS) of amorphous InGaZnO thin-film transistors (a-IGZO TFTs) are investigated. It is observed that under PBS, the threshold voltage shift (?Vth) increases with the increased value of the gate-bias stress voltage (VStress), which is due to the enhanced electron trapping at/near the interface of the channel and the gate insulator. However, under NBS, the ?Vth is nearly unaffected by the Vstress. As the NBS-induced negative ?Vth is resulted from electron-detrapping from the donor-like states related to oxygen vacancies, it is supposed that the rate of electron-detrapping is not sensitive to the negative gate-bias voltage. The influence of N2O plasma back-channel treatment is also studied. The stability under NBS is effectively improved after the N2O plasma treatment, which originates from the decreased density of oxygen-vacancy related donor-like states within the a-IGZO channel layer.
关键词： thin-film transistors,N2O plasma treatment.,amorphous InGaZnO,gate-bias stress,stability
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Interconnect Technology Conference (IITC) - Santa Clara, CA, USA (2018.6.4-2018.6.7)] 2018 IEEE International Interconnect Technology Conference (IITC) - Spray Plasma Processing of Barrier Films Deposited in Air for Improved stability of Flexible Electronic Devices
摘要： We report on submicron organosilicate barrier films produced rapidly in ambient by a scalable spray plasma process for improved solar cell stability. The plasma is at a sufficiently low temperature to be compatible with flexible electronic devices. The thickness of the barrier films is tunable and fully transparent over the visible spectrum. The morphology and density of the barrier are shown to improve with the addition of a fluorine-based precursor. Thin-film perovskite solar cells with submicron coatings exhibited significant improvements in stability when exposed to light, heat, and moisture. X-ray diffraction measurements performed while heating showed the barrier film dramatically slows the formation of PbI2. When deposited on a flexible substrate, the barrier films exhibit no signs of cracking or delamination after 10,000 bending cycles on a 127 μm substrate with a bending radius of 1 cm.
关键词： barrier films,spray plasma processing,flexible electronics,perovskite solar cells,stability
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Research on the Characteristics of Optoacoustic Signal Induced by Optical Breakdown
摘要： Optical breakdown is a mechanism of Laser-generated sound effect, based on the theory of optical breakdown mechanism in this paper, Characteristics of the photo-acoustic signal of the optical breakdown are studied through experimental, including the excitation threshold and the photoacoustic signal, Domain and frequency domain characteristics and characteristics of acoustic signals as a function of laser pulse energy. Study on the relationship between photoacoustic signal and laser source may serve for further study on laser-generated sound and underwater applications.
关键词： optical breakdown,laser-generated sound,plasma,breakdown threshold
更新于2025-09-10 09:29:36
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[Advances in Experimental Medicine and Biology] Glycobiophysics Volume 1104 || Unraveling of Lipid Raft Organization in Cell Plasma Membranes by Single-Molecule Imaging of Ganglioside Probes
摘要： Gangliosides are involved in a variety of physiological roles and particularly in the formation and function of lipid rafts in cell membranes. However, the dynamic behaviors of gangliosides have not been investigated in living cells owing to the lack of fluorescent probes that behave like their parental molecules. This has recently been resolved by developing new fluorescent ganglioside analogues that act similarly to their parental molecules, synthesized by only chemical methods. We performed single fluorescent-molecule imaging and revealed that ganglioside probes dynamically enter and exit rafts containing CD59, a glycosylphosphatidylinositol (GPI)-anchored protein, both before and after stimulation. The residency time of our ganglioside probes in CD59 oligomers was 48 ms after stimulation. The residency times in CD59 homodimer and monomer rafts were 40 and 12 ms, respectively. These results reveal the first direct evidence that GPI-anchored receptors and gangliosides interact in a cholesterol-dependent manner. Furthermore, they demonstrate that gangliosides continually move in and out of rafts that contain CD59 in an extremely dynamic manner and at a much higher frequency than expected. In this chapter, we review methods for the development and single-molecule imaging of new fluorescent ganglioside analogues and discuss how raft domains are formed, both before and after receptor engagement.
关键词： GPI-anchored protein,Single-molecule fluorescence tracking,Cell plasma membrane,Raft domains,Fluorescent ganglioside probes
更新于2025-09-10 09:29:36