Wyniki wyszukiwania - BazTech

1

Przepływomierz cieplnoprzewodnościowy

Detka A., Kirczuk C., Wiśniewski K.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2005

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z. 153

157-160

EN

A thick layer gas sensor, fabricated in the Faculty of Microsystem Electronics and Photonics at Wrocław University of Technology has been used in the construction of a heat conductivity flowmeter. It was found, that about 60 % of the energy is dissipated from the heated sensor by heat conductivity of a surrounding gas at the atmospheric pressure. Two methods of the heater supply conditions have been studied: U=constant and T=constant. Measuring range of the designed heat coductivity flow-meter was 10(-2) W +20W.

2

Nowe konstrukcje wielowiązkowych lamp elektronowych dużej mocy dla potrzeb elektroniki mikrofalowej

Sobański J., Czarczyński W., Fabich R.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2005

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z. 153

59-66

EN

A short history of a new generation of vacuum microwave devices - travelling wave tubes (TWT) is presented. Conventional single-beam tubes have been compared with multibeam ones of the same output parameters. The multibeam tubes show much lower supply voltage and higher efficiency. Computer codes for multibeam TWT design have been described and discussed. Some codes, although mentioned in numerous publications, are not commercially available and other cannot be sold outside USA (eg. synthetic code CHRISTINE). Problems of generation and precise focusing of many parallel beams with high current density. In the presented work only commercial codes were used. Simulation results of existing electron gun obtained with E-gun code and Omni Trak code have been compared with the experimental data. Omni Track, HiPi and Magnum Codes (Field Precision) were also used for simulation of the system for generation, focusing and collecting for multibeam TWT with seven beams. The initial parameters for the TWT were calculated using a synthetic code SYNTWT (Istok).

3

Stałe austenityczne jako materiał konstrukcyjny urządzeń techniki próżni

Grodziński A., Marks J., Witowski A.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2002

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z. 143

15-24

EN

The construction material for vacuum equipments is mainly austenite steel (stainless steel). The composition and some properties important for vacuum technology of the different stainless steel type are discussed. The main preparation method of steel surface e.g. degreasing, surface polishing and thermal treatments in vacuum oxidizing athmosphere on degassing rate are also discussed. As the hydrogen is the main component of the gaseous phase in UHV and XHV the role of diffusion barrierformed on steel surfaces is shown. The barriers consist from thin chromium oxide layer formed during electro polishing and thermal treatment. Other method of a barrier formation is the deposition on stainless steel surface a thin layer of oxides and nitrides.

4

Problemy techniki próżniowej w technologii lamp mikrofalowych dużej mocy

Adydan M., Sobański J.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2002

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z. 143

25-32

EN

Despite the extended use of semicoductor devices in modern electronics, vacuum tubes, especially traveling wave tubes (TWT) still exhibit continuous improvement. In TWT used in satellite links, the efficiency, during the last 10 years has been improved from 40 to 80%. The main influence on the TWT parameters , as well as the life time, has the vacuum inside the tube during the whole time of exploitation. The knowledge about the vacuum changes during processing and exploitation of the tubes makes possible to extend the life time of TWT to 10(5) hours or more. In our presentation we want to give a review of existing microwave tubes, especially TWT, and also the vacuum problems during manufacturing of these tubes in our Institute.

5

Charakteryzacja wzorca wysokiej próżni z dynamiczną ekspansją gazu w oparciu o model globalny

Szwemin P.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2002

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z. 143

33-44

EN

The paper is concentrated on the gas flow modeling in high vacuum standards with the dynamic expansion of gases. The weakness of traditional model, which bases on the electrical circit`s analogy, has motivated the author to elaborate a new, global model. The macroscopic parameters as the gas number density and the gas flux density in the local volumes of the calibration chamber are evaluate on the base of the molecules behavior in microscopic scale of this model. The molecules are traced in the whole space of the high vacuum standard. Its inner surfaces are described by the mathematics equations as close as possible as well as the gas molecules interactions are also described by experimentally well confirmed scattering law. Using this model it is possible to study even the influence of mutual relations between the system elements. By this way it will be also possible to find the source of systematic differences between the particular high vacuum standards.