Wyniki wyszukiwania - BazTech

1

Analiza porównawcza modeli profilu gęstości ładunków jonosfery wykorzystywanych do predykcji sygnałów w kanałach KF

Uljasz Bogdan, Ziółkowski Cezary

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2023

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nr 4

301--304

PL

Profil gęstości ładunków jonosfery jest podstawą dla modelowania i analizy jakości transmisji sygnałów w łączach KF (fale krótkie) dalekiego zasięgu. Niniejszy artykuł dotyczy oceny dokładności odwzorowania krzywej gęstości ładunków na bazie pięciu wybranych modeli profili. Opisano miarę i metodę analizy porównawczej warunkujące ocenę błędu aproksymacji danych pomiarowych. Prezentowane wyniki są podstawą do wyboru modelu profilu, który zapewnia skuteczne odwzorowanie wpływu warunków propagacyjnych jonosfery na transmitowane sygnały.

EN

The ionosphere charge density profile is the basis for modeling and analyzing the quality of signal transmission in long-range HF (ang. High Frequency) links. This article concerns the assessment of the accuracy of mapping the charge density distribution based on five selected profile models. The measure and method of comparative analysis conditioning the assessment of the measurement data approximation error are described. The presented results are the basis for the selection of a profile model that provides an effective representation of the influence of ionosphere propagation conditions on the transmitted signals.

2

Empirical method for modeling the percent depth dose curves of electron beam in radiation therapy

Chen Dong-Ji, Zhang Yan-Shan, Ye Yan-Cheng, Wu Jia-Ming

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 4

315--321

EN

Introduction: This study presents an empirical method to model the electron beam percent depth dose curve (PDD) using the primary and tail functions in radiation therapy. The modeling parameters N and n can be used to derive the depth relative stopping power of the electron energy in radiation therapy. Methods and Materials: The electrons PDD curves were modeled with the primary-tail function in this study. The primary function included exponential function and main parameters of N, µ while the tail function was composed by a sigmoid function with the main parameter of n. The PDD for five electron energies were modeled by the primary and tail function by adjusting the parameters of N, µ and n. The R50 and Rp can be derived from the modeled straight line of 80% to 20% region of PDD. The same electron energy with different cone sizes was also modeled with the primary-tail function. The stopping power for different electron energies at different depths can also be derived from the parameters of N, µ and n. Percent ionization depth curve can then be derived from the percent depth dose by dividing its depth relevant stopping power for comparing with the original water phantom measurement. Results: The main parameters N, n increase, but µ decreases in primary-tail function when electron energy increased. The relationship of parameters n, N and LN(-µ) with electron energy are n = 31.667 E0 - 88, N = 0.9975 E0 - 2.8535, LN(-µ) = -0.1355 E0 - 6.0986, respectively. Stopping power of different electron energy can be derived from n and N with the equation: stopping power = (−0.042 ln NE0 + 1.072)e(−n−E0·5·10−5+0.0381·d), where d is the depth in water. Percent depth dose was derived from the percent reading curve by multiplying the stopping power relevant to the depth in water at certain electron energy. Conclusion: The PDD of electrons at different energies and field sizes can be modeled with an empirical model to deal with the stopping power calculation. The primary-tail equation provides a uncomplicated solution than a pencil beam or other numerical algorism for investigators to research the behavior of electron beam in radiation therapy.

3

Monte Carlo study of medium-energy electron penetration in aluminium and silver

Aydın A., Peker A.

Nukleonika

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2015

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Vol. 60, No. 2

361--366

EN

Monte Carlo simulations are very useful for many physical processes. The transport of particles was simulated by Monte Carlo calculating the basic parameters such as probabilities of transmitted–reflected and angular-energy distributions after interaction with matter. Monte Carlo simulations of electron scattering based on the single scattering model were presented in the medium-energy region for aluminium and silver matters. Two basic equations are required the elastic scattering cross section and the energy loss. The Rutherford equation for the different screening parameters is investigated. This scattering model is accurate in the energy range from a few keV up to about 0.50 MeV. The reliability of the simulation method is analysed by comparing experimental data from transmission measurements.

4

Impact of the mass and other parameters of charged particles on the results of laser resonance acceleration

Dubik A., Małachowski M. J.

Biuletyn Wojskowej Akademii Technicznej

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2014

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Vol. 63, nr 1

13-42

EN

Theoretical and numerical analyses are presented concerning the conditions at which the charged particles of different masses can be accelerated to significant kinetic energy in the circularly polarized laser or maser beams and a static magnetic field. The studies are carried out using the analytical derivations of the particles dynamics and theirs kinetic energy. The presented illustrations enabled interpretation of the complex motion of particles and the possibilities of their acceleration. At the examples of an electron, proton and deuteron, the velocity, kinetic energy and trajectory as a function of the acceleration time at the resonance condition are illustrated in the appropriate graphs. The particles with larger masses require the application of enhanced magnetic field intensity at the resonance condition. However, this field intensity can be significantly reduced if the particles are preaccelerated.

PL

Stosując metody teoretyczną i numeryczną przebadano warunki, w których naładowane cząstki o rożnych masach można przyspieszać do znacznej energii w kołowo spolaryzowanej laserowej bądź maserowej wiązce z dodatkowym statycznym polem magnetycznym. Badania przeprowadzono za pomocą wyprowadzonych analitycznych relacji dotyczących dynamiki i kinetycznej energii cząstek. Dzięki stosunkowo licznym wykresom stała się możliwa interpretacja dość złożonego ruchu cząstek oraz przebiegu ich akceleracji. Na przykładach elektronu, protonu i deuteronu zostały zilustrowane zależności od czasu trwania akceleracji takich wielkości jak kształt trajektorii oraz kinetyczna energia. Wszystkie ilustracje dotyczą warunku rezonansu, czyli synchronizacji ruchów obrotowych cząstki i wektora natężenia pola elektrycznego. Czym większa masa cząstki, tym większe natężenie stałego pola magnetycznego jest niezbędne do uzyskania warunku synchronizacji. Jednak to natężenie można znacznie zredukować, jeśli cząstka będzie posiadała prędkość początkową.

5

Characterization of powders used for LPPS Thin Film plasma spraying of thermal barrier coatings

Góral M., Drajewicz M., Pytel M., Kotowski S.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 47, nr 2

157--165

EN

Purpose: The authors described in this article the basic properties of materials used for spray process of thermal barrier coatings under low pressure The characteristic of selected powders applied for bond-coats and outer ceramic layer was introduced. The authors presented the analysis of powders based on zirconium oxide stabilized by yttrium oxide, magnesium and calcium. Design/methodology/approach: The described powders was analyzed by scanning electron microscopy and particle distribution by IPS U analyzer. Findings: The ceramic powders were characterized by irregular particle shape caused by grinding process. The only exception was Metco 204 powder, with spheroid-shaped particles. Research limitations/implications: The ceramic powders were made of zirconium oxide, which was stabilized by different types of oxides: yttrium (Metco 204), calcium (Metco 201) and magnesium (Metco 210). It is necessary to assess influence of the oxide, stabilizing the yttrium oxide, on stability of obtained ceramic layer of TBC coating. Practical implications: Powders analysed in the article will be submitted to plasma spraying process with different methods. Originality/value: The ceramic powder used for LPPS-Thin Film process were first time described.

6

Ujawnienie historii radiacyjnej napromieniowanego elektronami krzemu otrzymanego metodą Czochralskiego poprzez po-radiacyjną obróbkę termiczną

Misiuk A., Jung W., Prujszczyk M., Bak-Misiuk J., Felba J.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 7

29-31

PL

Domieszkowany borem krzem otrzymany metodą Czochralskiego (Cz-Si), o orientacji (001) i o koncentracji domieszki tlenowej ok. 9x1017 cm-3, został napromieniowany elektronami o energii 40 keV i dawkach do 2.5x1016 cm-2. W wyniku wygrzewania w temperaturze do 1400 K, także pod wysokim ciśnieniem (do 1,2 GPa) argonu, ulega wydatnej zmianie koncentracja elektronów przewodnictwa oraz struktura defektowa Cz-Si. Podano wyjaśnienie tego zjawiska i zaproponowano jego wykorzystanie do ujawnienia napromieniowania krzemu elektronami.

EN

Boron doped (001) orientated Czochralski grown silicon (Cz-Si) with concentration of oxygen interstitials of about 9x1017 cm-3, was irradiated with electrons (energy 40 keV, doses up to 2.5x1016 cm-2). In effect of annealing at 1400 K, also under high hydrostatic Ar pressure, up to 1.2 GPa, concentration of carriers in the conduction band and defect structure of Cz-Si are changing markedly. Explanation of this effect is proposed and its application for revealing the electron irradiation history of Cz-Si is suggested.

7

The azimuthal anisotropy of electrons from heavy flavor decays in square root (sNN) = 200 GeV Au-Au collisions by PHENIX

Sakai S.

Nukleonika

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2006

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Vol. 51,suppl.3

33-35

EN

The transverse momentum dependence of the azimuthal anisotropy parameter v2, the second harmonic of the azimuthal distribution, for electrons at mid-rapidity (|eta| < 0.35) has been measured with the PHENIX detector in Au+Au collisions at square root(sNN) = 200 GeV with respect to the reaction plane defined at high rapidities (|eta| = 3-4). From the result, we have calculated non-photonic electron v2, which is expected to reflect the heavy-flavor azimuthal anisotropy, by subtracting v2 of electrons from other sources such as photon conversions, Dalitz decay etc.

8

Ambipolar charge carrier transport in liquid crystals

Iino H., Hanna J.

Opto-Electronics Review

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2005

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Vol. 13, No. 4

295-302

EN

We review the electron transport in both smectic and discotic liquid crystals with the updated experimental results, and discuss the ambipolar carrier transport in these materials. We indicate that the intrinsic nature of charge carrier transport in liquid crystals is probably ambipolar, in which both electronic and ionic charges are transported basically irrespective of their polarity, and that the ionic transport in these liquid crystals is extrinsic and induced by photo-ionization of chemical impurities. Furthermore, we discuss the importance of this unique features of charge carrier transport in the liquid crystals in the future development of new optoelectronic device applications that cannot be achieved with conventional organic semiconductors.

9

Błędy ułożenia - czym są i od czego zależy ich energia.

Wróbel M.

Inżynieria Materiałowa

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2001

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R. XXII, nr 6

1024-1032

PL

W pracy przedstawiono definicje błędów ułożenia (BU) i energii błędu ułożenia, rozróżniając energię hipotetycznego (nieograniczenie rozciągłego) błędu ułożenia, na który nie wpływają dyslokacje (EBU) od energii błędu ułożenia ograniczonego dyslokacjami częściowymi (efektywna energia błędu ułożenia EEBU). Przedyskutowano również ograniczenia traktowania energii błędu ułożenia jako miary względnej stabilności struktur krystalicznych. Krótko przedstawiono podstawy związku EBU z oddziaływaniami atomów i elektronów oraz przedyskutowano przyczyny wyznaczonych zależności EBU od składu chemicznego stopów i od temperatury.

EN

The concept of the stacking faults (SF), the stacking energy (SFE) and selected examples of typical SFs in the face-centered cubic (fcc) structure and in the hexagonal close-packed (hcp) structure is presented. The sequence of stacking and SFs have been described by some letters which designate position of the successive atomic planes. Additionally, Frank notation system as well as notation introduced by Jagodziński were explained and used. Some experimental SFE values for selelcted metals are collected.

10

Particle accelerators for industrial processing. Part 2

Scharf W., Wieszczycka W.

Eksploatacja i Niezawodność

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2001

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nr 4

4-14

EN

The applications of over 1000 electron beam (EB) accelerator processors used recently worldwide span technological fields from material modification to medical sterilization and food processing. The performance level achieved by the main manufacturers is demonstrated by some selected parameters of processors in the energy range from 0.1 MeV to 10 MeV. The design of the new generation of low cost compact in-line and stand-alone accelerators is discussed.

11

Long-range potential for excess electron surface states on helium clusters

Jortner J., Rosenblit M.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7S

1447-2453

EN

An excess electron bound to a ((4)He)N cluster (number of constituents N>/=3 x 10(5) and cluster radius R>/=R-c=149 A) exhibits a divergence of the first moment {r} of the charge distribution near the localization threshold (R=R-c), obeying the scaling law {r} infinity (R - R-c)(-1). The asymptotic form of the elektron-cluster potential has to be modified to include Casimir-Spruch retardation effects, which provide a small repulsive contribution O(h/mc)r(-1).

12

Is lepton mass-spectrum Ffnite?

Góral A.B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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1998

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Vol. 46, nr 4

383-397

EN

The head question is answered in a single-valued manner on a basis provided by this authors thinking scheme: it turns out that only four massive leptons accompanied by four massless neutrinos are allowed. Among the allowed set of leptons heavy electron has been found, appending known three: electron, muon and tauon, so far, not admitted by physicists community.