In this paper, a wideband 220-GHz sheet-beam traveling-wave tube (TWT) based on staggered double vane slow-wave structure (SWS) is investigated. A novel method of loading the attenuator into the SWS for suppressing backward wave oscillation is proposed. In addition, a novel focusing electrode of the sheet beam gun is carried out in this paper, which is a whole structure but divided into two parts artificially, one is used to compress the electron beam in X-direction and the other is used to compress the electron beam in Y -direction. In addition, a novel anode is redesigned to reduce the defocusing effect caused by the equipotential surfaces. A nonuniform periodically cusped magnet is used for focusing the sheet electron beam, which is predicted to exhibit 100% beam transmission efficiency in a 75-mm length drift tube. The high-frequency characteristics of the SWS and the beam-wave interaction are also studied. The results reveal that the designed TWT is expected to generate over 78.125-W average power at 214 GHz, and the 3-dB bandwidth is 31.5 GHz, ranging from 203 to 234.5 GHz.Index Terms-220-GHz traveling-wave tube (TWT), attenuator, electron gun, focusing electrode, periodically cusped magnet (PCM), sheet electron beam, slow-wave structure (SWS), staggered double vane.

To improve the efficiency of beam‐wave interaction and the gain of the microstrip angular log‐periodic meander‐line (MALPML) travelling wave tube (TWT), a modified phase velocity tapered MALPML (PVT‐MALPML) with 45° chamfer is proposed in this study. Compared with MALPML slow wave structure (SWS), the PVT‐MALPML SWS has better transmission characteristics. Meanwhile, the beam‐wave interaction simulation results show that a higher gain and electron efficiency can be produced by the PVT‐MALPML TWT. By using the novel PVT‐MALPML SWS, the properties of the radial TWT is further improved to meet the requirements of electronic system to TWTs.

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Prodrug-based nanoassemblies have been developed to solve the bottlenecks of chemotherapeutic drugs. The fabricated prodrugs usually consist of active drug modules, response modules, and modification modules. Among three modules, the response modules play a vital role in controlling the intelligent drug release at tumor sites. Herein, various locations of disulfide bond linkages were selected as response modules to construct three Docetaxel (DTX) prodrugs. Interestingly, the small structural difference caused by the length of response modules endowed corresponding prodrug nanoassemblies with unique characteristic. α-DTX-OD nanoparticles (NPs) possessed the advantages of high redox-responsiveness due to their shortest linkages. However, they were too sensitive to retain the intact structure in the blood circulation, leading to severe systematic toxicity. β-DTX-OD NPs significantly improved the pharmacokinetics of DTX but may induce damage to the liver. In comparison, γ-DTX-OD NPs with the longest linkages greatly ameliorated the delivery efficiency of DTX as well as improved DTX’s tolerance dose.

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