Near-field microwave microscopy (NSMM) is a promising technique for the non-destructive, high-resolution imaging of electrical and dielectric properties at microscale. However, its performance highly sensitive to probe-to-sample distance, often requiring extremely close proximity, which limits practical application in device manufacturing, especially scenarios involving coatings packaging. In this study, we propose distance inversion method based on dual-port symmetrical probe improve...

Because of the large quantities edges, graphene can serve as an efficient edge emitter for field emission (FE). Cesium iodide (CsI) coating was promising to enhance electron and utilized in FE applications. In this work, sheets after electrophoretic deposition (ED) studied. Electron property GS obviously improved by with CsI. The turn-on decreased from 4.4 2.5 V/ μm; threshold 9 5.8 V/μm, respectively. This improvement must due a higher effective density site generated around surface...

The recent rapid growth of the semiconductor industry in development high power microwave source has open a new promising avenue by full electronic control over electromagnetic field towards improve heating performance. In this paper, coupled and heat transfer model was built to simulate multiple chicken blocks with temperature-dependent dielectric properties dependent on solid-state oven. Owing ability precisely frequency, temperature distribution simulated for fixed frequency compared...

Graphene-carbon nanotube hybrid is prepared by an in situ growth of vertical graphene sheets on carbon nanotubes (CNTs), using one-step plasma-enhanced chemical vapor deposition, without catalyst. TEM analysis indicates that the accordance with defects introduced high-energy ion bombardment microwave plasma and expands epitaxial growth. The results suggest method ideal for preparing uniform graphene-carbon demonstrate a categorical explanation mechanism graphene-CNTs hybrid. Because its...

Lateral orientation and aggregation of the graphene sheets limited field enhancement paper (GP). To improve GP, argon plasma treatment was induced to destroy cause formation surface protrusions. After Ar treatment, turn-on threshold GP were reduced from 2.3 V/μm 1.6 4.4 3.0 V/μm, respectively. The attributed Scanning electron microscopy hydrophobicity had been used prove morphology change after treatment.

High-current field emitters are made by graphene paper consist of aligned sheets. Field emission luminance pattern shows that their electron beams can be controlled rolling the from sheet to cylinder. These specific would useful vacuum devices and beam lithograph. To get high-current emission, is rolled array form cannon. Due array, cannon have high current. Besides current, also tolerable with excellent stability. With good properties, these bring application insight.

Usually, the fluidity of liquids is considered to make temperature field uniform, when it heated, because heat convection, but there something different microwave heating. The top always highest in liquid heated by microwaves. In this paper, multiphysics simulation and experimental comparison distribution water alcohol reheated rice are performed. order microwaves cut-off waveguide used control heating improve uniformity. results show that modified glass cup with 7 cm metal coating a oven,...

The effects of rare earth yttrium (Y) additions and the heat treatment process on microstructure mechanical properties as-cast ADC12 aluminum alloy have been investigated. results showed that primary Si crystals were significantly refined from long axis to fibrous or granular when Y content was 0.2 wt%. Compared matrix, mean area aspect ratio decreased by 92% 75%, respectively. Moreover, Fe-rich phases spheroidized with a small average size during solid solution. It also noted copper-rich...

In this paper, the effect of heat treatment (solution and artificial aging) on microstructure properties as-cast Al5Si1Cu0.5Mg aluminum alloy its composite reinforced with 1.5 wt.% SiC particles was studied. The results showed that at 520 °C optimal solution time for is 9 h 6 h, respectively. After treatment, these two materials consists a uniform distribution nearly spherical eutectic Si skeletal γ phase, furthermore, phase smaller more dispersed. aging 175 dispersed finer than whole Al2Cu...

Graphene emitters with high enhancement factor and ultra low emission field were exfoliated from carbon fibers in cloth. This method made the graphene sheets to stay on fiber used, situ, as emitters. Due their multistage intrinsic good contact, electron these required field. The threshold-field corresponding current density of 1 mA/cm2 was about 0.7 V/μm. attributed effects aspect ratio geometry

A high emission current with relatively low operating voltage is critical for field cathodes in vacuum electronic devices (VEDs). This paper studied the performance of single-wall carbon nanotube (SWCNT) cold prepared by screen printing a silver paste buffer layer. The layer can both enforce adhesion between SWCNTs and substrate, decrease their contact resistance, so as to increase current. Compared mixing CNTs printed cathodes, avoid excessive wrapping slurry effective area reduce voltage....

A bulb tubular pump unit is a horizontal composed of water and with an electric motor installed. Electric motors, transmission equipment, bearings are usually placed in the bulb. The located flow channel has relatively narrow space. Therefore, shape significant influence on pattern efficiency channel. In this study, CFX 19.2 software was employed to optimize hydraulically according its geometry parameters. research results indicate that at tail elliptical better, hydraulic loss section...

A graphene frequency tripler (GFT) is proposed. The similar to anti-parallel diodes, which has nonlinear characteristic. In order improve the efficiency of GFT, output port GFT uses reflector networks recover power fundamental and fifth harmonic wave. According mechanism, a sample designed, fabricated, measured. its operation 12 GHz 30 GHz, minimum conversion loss −24.2 dB can be obtained at 18 when input 14 dBm.

In this letter, a nondestructive local characterization of graphene fabricated by the reduction method on oxide aqueous was demonstrated using near-field scanning microwave microscopy (NSMM). The dielectric properties films have been extracted to analyze quality graphene. Clear images defects film were obtained mapping resonant frequency, f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> , and factor, Q, given area. results demonstrate...

Improvements in field emission (FE) of graphene sheets were demonstrated by radio frequency magnetron sputtering with magnesium oxide (MgO). Following MgO coating, the turn-on is decreased from 6.3 to 3.8 V/μm, and threshold 9 6.5 V/μm. The deposited nanoparticles not only decrease but also enhance tolerance ability various pressure conditions. Field stability measurements indicated better lifetime for MgO-coated emitter. Meanwhile, atomic force microscopy, scanning electron transmission...