in the present study, aminoazines were prepared from the reaction of amidrazone hydroiodide with various aromatic aldehydes in the presence of a solid base under microwave irradiation with power level of 850 w for 2-7 min in high yields. the amidrazone hydroiodide can also be prepared by the reaction of s-methyl isothiobenzamide hydroiodide and hydrazine in methanol under nitrogen gas. all synt...

in this pepper fe2o3 nanoparticles were synthesized via a fast microwave method. then fe2o3-tio2 nanocomposites were synthesized by a sonochemical-assisted method. the prepared products were characterized by x-ray diffraction pattern, scanning electron microscopy and fourier transform infrared spectroscopy. the photocatalytic behaviour of fe2o3-tio2 nanocomposites was evaluated using the degrad...

In this paper, to substitute the existing TWTA(Travailing Wave Tube Amplifier) component in small radar system, we developed Ku band SSPA(Solid-State Power based on fabrication of power MMIC (Monolithic Microwave Integrated Circuit) chips. For development 500 W SSPA, 40 W-grade was designed by ADS(Advanced Design System) at Keysight company with UMS GH015 library, and processed foundry service....

Abstract An ultrashort H‐plane sheet beam traveling‐wave tube (SB‐TWT) coupler without transition structure is proposed. The adopts a new idea of directly coupling the microwave from slow‐wave circuit (SWC) and optimizes matching by introducing an asymmetric circular ridge on E‐plane coupled waveguide. As result, length SB‐TWT reduced more than 3λ to 1λ. At same time, tunnel area enlarged twice...

Understanding the generation and growth of nonlinear harmonic (and intermodulation) distortion in microwave amplifiers such as traveling wave tubes (TWTs), free electron lasers (FELs), and klystrons is of current research interest. Similar to FELs, the nonlinear harmonic growth rate scales with the harmonic number in TWTs. In klystrons, the wave number scaling applies to the nonlinear harmonic ...

The principle of operation of intense radiation devices such as microwave tubes, free-electron lasers, and masers, is based on a distributed interaction between an electron beam and electromagnetic radiation. Some of the effects emerging during the interaction involve a continuum of frequencies in their broadband spectrum. We developed a three-dimensional, space-frequency theory for the analysi...

Two novel sources of variable frequency microwave energy with increased efficiency are described in this paper: a backward wave oscillator (BWO) with auto modulation of electron emission and a two-section BWO, which second section operates in the traveling wave tube (TWT) mode. In the first case, the BWO output is connected through a section of a slow-wave structure to the control electrode of ...

This paper presents the design, development and realization of a fast and novel process for the synthesis of 3C silicon carbide (β-SiC) nanorods and submicron powder. Using SiO₂ (or Si) and activated carbon (AC), this process allows β-SiC to be synthesized with almost 100% purity in timeframes of seconds or minutes using multimode microwave rotary tube reactors under open-air conditions. The sy...

2014 The atomic nitrogen metastable densities of N(2D) and N(2P) have been measured by optical absorption in a continuous glow dis harge. Electronic densities have been measured with a microwave resonant cavity. The evolution of N(2D) and N(2P) densities as a function of electronic density allows the estimation of the overall creation coefficient by electronic collisions CeM : e + N2 $$ e + N(2...

A cyclotron-resonance maser (CRM) is implemented in a periodic quadrupole waveguide. The device oscillates at the fundamental and high harmonics of the cyclotron frequency. This CRM employs a tenuous low-energy electron beam ( approximately 10 keV, 0.2 A). The periodic structure consists of an array of disks along the quadrupole transmission line, hence it combines both azimuthal and axial peri...