The dual-mode double-gap resonator with asymmetrrical strip line on the suspended ceramic substrate
A new dual-mode double-gap resonator on the basis of asymmetrical suspended stripline for miniature klystron type microwave tubes with field emitter arrays (FEA) cathodes was investigated. The resonator has a smaller size and mass when a doublegap capacitive segment of each quasi-lumped resonator consists of two assimmetrical strip conductors on opposite sides of the substrate and both inductive segments are grounded. This resonance circuit has two oscillation modes (anti-phase and in-phase). On the basis of the 3-D modeling found that such oscillatory systems can achieve the excitation of these modes with multiplicity of frequencies to = 2 with a good efficiency of interaction of electrons with microwave fields.
A double‐gap klystron type resonator with inductive quasi‐fractal elements
Electrodynamic characteristics and parameters of the double‐gap klystron resonator with the inductive microstrip elements on the suspended ceramic substrate has been investigated. The inductive part of a resonator made on the basis of a quasi‐fractal Sierpinski's triangle, and a capacitor part, made between end faces of the multi‐channel drift tubes and forming a double gridless gap. The developed resonator can find application in micro vacuum klystron devices working in the systems of telecommunication and navigation in 1‐ and multi‐frequency mode of operation.
Preparation of hydrophilic poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation
Abstract Hydrophilic microporous hollow fiber membranes were prepared via thermally induced phase separation (TIPS). Poly(vinyl butyral) (PVB) and three kinds of polyethylene glycols (PEG) with the molecular weight of 200, 400 and 600 were used as polymer and diluents. In all cases, liquid–liquid (L–L) phase separation occurred and asymmetric cellular structures with the smaller pores at the outer surface were obtained. The properties of membranes such as pore size, water permeability, solute rejection and intensity were investigated by changing molecular weight of PEG, concentration of PVB, composition of the bath and air gap distance. The smaller molecular weight of PEG, the more PEG in the bath and the shorter air gap distance resulted in the higher water permeability, the lower solute rejection property and the lower mechanical strength.