- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
EM-Wave Diffraction by a Finite Plate with Dirichlet Conditions in the Ionosphere of Cold Plasma
摘要： In the current communication, the problem of plane wave di?raction by a conductible plate of ?nite length in the presence of cold plasma is investigated. The boundary-value problem corresponding to this model is formulated by Fourier transform which then leads to the Wiener?Hopf equation. The resulting equation has been solved by the Wiener?Hopf procedure in a standard way. The separated ?eld (di?racted ?eld) is analyzed in an anisotropic medium using asymptotic expansion and modi?ed stationary phase method. The problem can be made simple by assuming ε2 → 0, where ε2 is the element of permittivity tensor. This happens, if the operating frequency is assumed to be very large as compared to ωc (cyclotron frequency) while it is of same order of ωp (the plasma frequency). The case ε1 = 1, ε2 → 0 leads to the results for soft plate of ?nite length in an isotropic medium. Graphical study is performed to investigate the behavior of separated ?eld for various physical parameters for isotropic and anisotropic media.
关键词： Wiener-Hopf technique,asymptotic expansion,cold plasma,electromagnetic wave,diffraction
更新于2025-09-04 15:30:14
-
Discharges of plasma induced by hypervelocity impact on the solar array with different substrate structures1
摘要： The purpose of the paper is to investigate the discharge of the plasma generated by a projectile hypervelocity impact on solar array with three kinds of different substrates at the 60? incidence angle and the external applied voltage of 100 voltage. Four sets of experiments were performed to impact solar arrays with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate by using two-stage light gas gun loading system and discharge measurement system established. Experimental results showed that discharge voltage and discharge current of the solar array with CFRP Aluminum honeycomb sandwich substrate are the most strongest among the solar array with CFRP Aluminum honeycomb sandwich substrate, Aluminum honeycomb sandwich substrate and the aluminum substrate. This work will be helpful to improve the material and substrate’ structure of the solar arrays in spacecrafts.
关键词： Hypervelocity impact,solar array with different substrate,discharge voltage,plasma,discharge current
更新于2025-09-04 15:30:14
-
Gastric Hemangioma Treated with Argon Plasma Coagulation in a Newborn Infant
摘要： Gastric hemangioma in the neonatal period is a very rare cause of upper gastrointestinal bleeding. We present a case of hemangioma limited to the gastric cavity in a 10-day-old infant. A huge, erythematous mass with bleeding was observed on the lesser curvature side of the upper part of the stomach. Surgical resection was ruled out because the location of the lesion was too close to the gastroesophageal junction. Medical treatment with intravenous H2 blockers, octreotide, packed red blood cell infusions, local epinephrine injection at the lesion site, application of hemoclip, and gel-form embolization of the left gastric artery did not significantly alter the transfusion requirement. Hemostasis was achieved with endoscopic argon plasma coagulation (APC). After two sessions of APC, complete removal of the lesion was achieved. APC was a simple, safe and effective tool for hemostasis and the ablation of gastric hemangioma without significant complications.
关键词： Neonate,Hemangioma,Stomach,Argon plasma coagulation
更新于2025-09-04 15:30:14
-
High-efficiency electron-beam-pumped sub-240-nm ultraviolet emitters based on ultra-thin GaN/AlN multiple quantum wells grown by plasma-assisted molecular-beam epitaxy on <i>c</i> -Al <sub/>2</sub> O <sub/>3</sub>
摘要： We report the internal structures and emission properties of GaN/AlN single- and multiple-quantum-well (QW) heterostructures with well widths of dw = 1–4 monolayers (MLs), grown by plasma-assisted molecular-beam epitaxy on c-sapphire at metal-rich conditions and low temperatures (>700 °C). The formation of plane QWs with abrupt symmetrical interfaces is con?rmed by both scanning transmission electron microscopy and X-ray di?raction analysis. Pulse-scanning and continuous-wave output powers of 150 and 28 mW, respectively, at a peak emission wavelength of 235 nm were achieved at 300 K in an electron-beam-pumped deep-ultraviolet (1.5 ML-GaN/5.5 nm-AlN)360 multiple-QW emitter with a maximum e?ciency of 0.75%.
关键词： plasma-assisted molecular-beam epitaxy,electron-beam-pumped,deep-ultraviolet emitters,GaN/AlN,quantum wells
更新于2025-09-04 15:30:14
-
Hot spots for GPCR signaling: lessons from single-molecule microscopy
摘要： G protein-coupled receptors (GPCRs) are among the best-studied membrane receptors, mainly due to their central role in human physiology, involvement in disease and relevance as drug targets. Although biochemical and pharmacological studies have characterized the main steps in GPCR signaling, how GPCRs produce highly specific responses in our cells remains insufficiently understood. New developments in single-molecule microscopy have made it possible to study the protein–protein interactions at the basis of GPCR signaling in previously inconceivable detail. Using this approach, it was recently possible to follow individual receptors and G proteins as they diffuse, interact and signal on the surface of living cells. This has revealed hot spots on the plasma membrane, where receptors and G proteins undergo transient interactions to produce rapid and local signals. Overall, these recent findings reveal a high degree of dynamicity and complexity in signaling by GPCRs, which provides a new basis to understand how these important receptors produce specific effects and might pave the way to innovative pharmacological approaches.
关键词： single-molecule microscopy,plasma membrane,GPCR signaling,protein–protein interactions,pharmacological approaches
更新于2025-09-04 15:30:14
-
Enhanced dielectric strength and energy storage density in BaTi0.7Zr0.3O3 ceramics via spark plasma sintering
摘要： Barium zirconate titanate (BaTi0.7Zr0.3O3) ceramics were prepared via spark plasma sintering (SPS) and conventional solid-state sintering (CS). Both samples exhibited single phase nature as confirmed from the X-ray diffraction analysis. Compared with CS sample, more homogeneous microstructure with smaller grain size was observed in the SPS sample, which greatly improved the dielectric strength of BaTi0.7Zr0.3O3 ceramics from 40 (CS) to 170 kV/cm (SPS). Although the polarization of SPS sample was lower than that of CS sample under the same applied electric field, the maximum energy storage density was improved to 0.51 J/cm3, which was about 4.5 times higher than that of the CS sample (0.12 J/cm3). Moreover, finite element simulation on the local dielectric field distribution was carried out, and the effects of microstructure on the dielectric strength were further confirmed.
关键词： BaTi0.7Zr0.3O3,energy storage density,spark plasma sintering,dielectric strength
更新于2025-09-04 15:30:14
-
Methods of improving spatial resolution for IR spectroscopy in atmospheric-pressure plasma systems
摘要： High-temperature, atmospheric pressure plasma systems operated in molecular gases present complex diagnostic challenges. Infrared spectroscopy has been used to make measurements of the absorbance spectrum of complex molecular gas mixtures and thereby calculate the concentrations and species temperatures in these systems. For atmospheric-pressure systems, high spatial gradients arise and high spatial-resolution measurements are thus desirable. Some systems have achieved increased spatial resolution by reducing the beam diameter. However, this increase in spatial resolution comes at the expense of the optical throughput. Here we propose modifying a commercial Fourier Transform, Infrared spectrometer system with a set of simple optical elements. This design allows for scannable, high spatial resolution absorbance spectrum measurements of a complex molecular gas mix. We analyze the signal-to-noise ratio for this design and compare it with the diameter reduction method. For sufficiently low plasma radiation levels, this design improves the signal-to-noise ratio relative to reducing the beam diameter size while transmitting nearly all of the beam power. However, whether this design can achieve the desired sub-mm spatial resolution depends on the radiating area of the infrared light source in the spectrometer.
关键词： Fourier Transform Infrared spectrometer,IR spectroscopy,spatial resolution,atmospheric-pressure plasma systems,signal-to-noise ratio
更新于2025-09-04 15:30:14
-
High-speed synthesis of heavily boron-doped diamond films by in-liquid microwave plasma CVD
摘要： In-liquid microwave plasma CVD (IL-MPCVD) processes allow rapid growth of diamond from mixtures of alcohols. Here, we report the first synthesis of polycrystalline boron-doped diamond (BDD) by an In-liquid microwave plasma CVD (IL-MPCVD) process from a mixture of alcohols and boron trioxide (B2O3). We simultaneously achieved high growth rates (up to 287 μm/h) and high boron concentrations (up to 7 × 1021 cm?3). We examined the growth mechanism and show that water generated by dissolution of B2O3 in the alcohol is key to rapid growth of BDD. Even with the same C:H:O ratio, diamond growth rate and nucleation density drastically decreased by addition of water. Water has an strong etching effect, which enables shifts diamond to grow in carbon rich conditions. Our results indicate that the C:H:O composition is not the only factor affecting diamond growth in IL-MPCVD processes but rather the actual substances used are also important. Finally, we evaluated the as-grown BDD film as a diamond electrode. Despite the high growth rate, oOur IL-MPCVD-grown BDD showed electrochemical properties comparable to those of BDD grown by the conventional CVD process in terms of its potential window (3.2 V) and peak separation (85 mV) in 1 mM K3[Fe(CN)6]. Owing to the high growth rate, IL-MPCVD is an effective technique for synthesizing BDD.
关键词： electrodes,chemical vapor deposition,diamond film,electrochemical,plasma CVD
更新于2025-09-04 15:30:14
-
[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Development of NbN polarization sensitive KID for Fusion Applications
摘要： In this paper, we present a preliminary study for the design of Kinetic Inductance Detectors (KID) sensitive to polarization, which will be employed in an innovative polarimetric system for fusion plasma diagnostics applications.
关键词： polarization sensitivity,Kinetic Inductance Detectors,NbN,fusion plasma diagnostics,polarimetry
更新于2025-09-04 15:30:14
-
Numerical Investigation for Scale-Up of an Electron Cyclotron Resonance Plasma for Fluorine-Doped Tin Oxide Thin Film Production
摘要： A low-temperature process is required to deposit ?uorine doped tin oxide (FTO) as a transparent conductive oxide on polyethylene terephthalate (PET) substrate, as the latter is polymeric and has a low melting point. An electron cyclotron resonance (ECR) plasma system is the best way to deposit metal oxide with high transparency and electrical conductivity at temperatures below 100 (cid:2)C. Characteristics of an ECR plasma include its high ionization energy and electron density; however, its use is limited in large-scale deposition. In order to overcome this limitation, a large-scale ECR plasma system with a dual microwave generator was designed by numerical investigation of a laboratory-scale ECR plasma system. FTO ?lms prepared in the laboratory-scale and large-scale systems were compared. The change in electrical resistivity and optical transmittance with deposition pressure in the large-scale ECR plasma system with dual linear microwave generator is similar to that observed in the laboratory-scale ECR plasma system. The velocity distribution of active species near the substrate in the large-scale ECR plasma system showed a very similar pattern to that in the laboratory-scale ECR plasma system over a range of 1.5 × 10?2 to 0.8 × 10?2 m/s. The electrical resistivity and optical transmittance of FTO ?lms deposited by a large-scale ECR plasma system using a dual microwave generator had respective values of 4.3 × 10?3 ～ 9.18 × 10?3 (cid:2) · cm and 86.5～88.2%.
关键词： Dual Microwave,ECR Plasma,Electrical Resistivity,Optical Transmittance,Fluorine-Doped Tin Oxide
更新于2025-09-04 15:30:14