Being interested in Talking and talkative has become the component of Bejing people's special identification feature and cultural characteristics.The feature of Beijing People's Parole reflects strong interest in politics and great sense of humor.Although it is only a kind of linguistic phenomenon,it embeds rich causes.It cannot be only treated as a linguistic phenomenon;there exists political,economic and cultural reasons behind the formation of linguistic phenomenon.
The electron beam of a K-band space traveling-wave tube (TWT) has been investigated in a beam measurement system in this article. The primary beam emitted from a Pierce-type electron gun is scanned by a Faraday cup probe, and the beam current density distribution and envelope are determined. The spent beam is also diagnosed with a novel retarding field energy analyzer (RFEA) by using the monopulse measurement method, and a comparison of velocity distribution between the experimental result and simulation is presented.
Based on a staggered double-grating slow wave structure with step-shaped grooves, the expressions of the electromagnetic field in it have been obtained and the formulae of the dispersion equation and coupling impedance have been solved by means of field matching method. As an example, a staggered double-grating slow wave structure for W band TWT application was used to calculate the characteristics of dispersion and coupling impedance using the formulae and CST-MWS code, and analyze the effect of the step dimension variation on the high frequency characteristics. Results show that the theoretical calculations are in good agreement with the CST-MWS code simulations, and the slow wave structure can improve the dispersion characteristics, enhance interaction bandwidth, while keeping a proper coupling impedance and mechanical intensity, which can to some extent compensate for the deficiency in the staggered double-grating slow wave structure with the rectangular-shaped grooves.
In order to solve the problems of poor insulation, low resolution and sparking etc., a retarding field energy analyzer is upgraded, simulated and analyzed to test and analyze the electron beam parameters accurately, which derive from the guns of traveling wave tubes and beams after beam-wave interaction, providing a reference for the design, performance improvement and development of the traveling wave tubes. The retarding energy analyzer with a controllable focusing voltage insulates high-voltage cylinder electrically from retarding mesh and applies a controllable small voltage between them. The second electrostatic lens accelerates and focuses the diverging beam near the area of the mesh, to weaken too much expansion in the region of the weak part that the first lens functions, due to space-particle effects and beam emittance, etc. and optimize the slope of the particle trajectory and resolution. Meanwhile, the whole structure tends to miniaturizition and lightweight. A computer code called CST is used to simulate the particle distribution in particle interfaces and the whole electric field distribution, and Matlab code helps data processing and exports the key parameters. Besides, the paper focuses on analyzing the optimization and improvement of the performance reflected by the resolution and Full Width at Half Maximum, etc. The result shows that this energy analyzer is competent to apply to the experiments of electron beams.
The paper outlined the supervision status of agricultural product safety of Huinong District of Shizuishan City of Ningxia,summarized the achievements and the problems of works of supervising.The countermeasure for improving supervising work was also put forward.
Experimental data mining is very important in the information discovery. Lots of data analysis is conducted in order to build the relative expression or correlation. However, the implicit parameters or implicit procedure parameters are usually ignored because a number of clear functions about the data exist. In fact, some new knowledge desired for the specific physical process and properties can be gotten by rebuilding the relationship among the experiment data. This paper presents a new data mining method to analysis the data completely and precisely, data reorganization and information synthesis, and its effect is proved through an actual experiment, radiation refrigeration experiment.
In order to enhance bandwidth of output circuit for klystron,the theory of overlapped mode is analyzed.Possibility of overlapped three-mode is illuminated.Gap-impedance frequency distribution for three-mode overlapped two-gap coupled cavity type output circuit(TTCC) is calculated via equivalent circuit method.Taking a TTCC with 3 GHz center frequency for instance,3D models for calculation are set up,and steps in designing this kind of output circuit are particularized.Parameters of structure are given.Relative bandwidth of 2 dB reaches 15%,and 19.3% of 1.5 dB is obtained by loading a filter through calculating gap-impedance frequency via field analysis method.
Taking 5kinds of pesticide as test drug and Bradysia odoriphagaas test pest,the effect of temperature on toxicity of seclected insecticides on Bradysia odoriphagawas evaluated,the toxicities of 5insecticides in 8、16、24℃ were studied with dripping ration liquid method,and their control efficiency in the field were also studied.The results showed that the toxicities of 5insecticides showed positive temperature effect.Among these insecticides,Imidacloprid showed the most obvious positive temperature effect,toxicity of Imidacloprid in 24℃ was 4.66times higher than that in 8℃. Methomyl,Clothianidin and Thiamethoxam's positive temperature effect were similar,and the positive temperature effect of Emamectin benzoate was minimum.In pot test,Emendation larvae mortality was 75.2% when roots were irrigated by Clothianidin 50 mg/L,which was 14.5%,24.8% and 28.2% higher than the same dose treatment of Methomyl, Imidacloprid and Thiamethoxam respectively.In field test,Clothianidin 100 mg/L and 50mg/L irrigating roots treatments were the best when processed 25days.The pesticide effect of Clothianidin were 100% and 95.2% while control efficiency of Methomyl 200mg/L was 84.2%.Pesticide effect of Imidacloprid and Thiamethoxam 100mg/L irrigating roots were 93.7%and 96.9%respectively,which were also better than Methomyl 200mg/L and 100mg/L. The 3kinds of neonicotinoids all had good pesticide effect on Bradysia odoriphaga.Among them,Clothianidin was outstanding and had a persistent control function on Bradysia odoriphaga.It was environment friendly and very suitable for the application in the fields.
A re-entrant klystron cavity is designed via MWS.The resonant frequency and characteristic impedance are optimized.Structure size of the cavity under f0=3.000 7 GHz R/Q=124.506 is obtained.Sensitivity about change of cavity size is analyzed,and the affects of perturbation of cavity size on electric parameters are discussed,which is useful for special engineering application.
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